IGS Magazine Summer 2021: The Nature of Collaboration by IGS Magazine

Intelligent Glass Solutions

“GREAT DISCOVERIES AND IMPROVEMENTS INVARIABLY INVOLVE THE COOPERATION OF MANY MINDS” - Alexander Graham Bell

LEVERAGING EXPERTISE Building High Performing Teams to Deliver Complex Façades

Summer 2021

HISTORY IN THE MAKING Towards the UN International Year of Glass 2022

Summer 2021 www.igsmag.com

I, ROBOT Robots and Humans Collaborate to Revolutionize Architecture

THE NATURE OF

COLLABORATION + A true visionary Dr. Hossein Rezai D" has "THE GLASS WOR

An IPL magazine

Quai Ouest, Boulogne-Billancourt; Architect: Brenac & Gonzalez Architects, Paris; Photographer: ©Stefan Tuchila, Paris; Glass Processor: Döring Glas, Berlin

CURVED GLASS

THE ARCHITECTURE OF WAVES

CONTOUR®

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30.03.2021 14:13:41

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Summer Edition 2021 A heartfelt thank you to ALL our wonderful contributors who ‘collaborated’ with IGS for this issue

The twisting façade of 8 Conlay, Image by KLCC. From ‘The Glass Word interview with Dr. Hossein Rezai’ on page 134

intelligent glass solutions | summer 2021

ADVANCED GLASS PUBLISHER’S WORD ENGINEERING

Standing on the Shoulders of Giants Bodycopy

Image credit: ‘Floating’ Sky Pool at Embassy Gardens. Sandor Szmutko / Shutterstock.com

intelligent glass solutions | summer 2021

ADVANCED GLASS PUBLISHER’S ENGINEERING WORD

ver the past 17 years, IGS Magazine has reflected the industry’s momentum, publishing expert opinion on the central issues that really matter, exclusively written for this publication by individuals and companies spearheading technology and innovations that are transforming the world we live in. Our objective from the outset and to this day has been to capture the industry’s sparkle and tap into the entrepreneurial spirit of the global architectural glass in areas of new technological solutions and share examples of best practice to as wide an audience as possible. The foundation of our mission is, by very nature, built on collaboration and a multidisciplinary meeting of minds: from our creative team, to editors, publicists, graphic designers and the authors who put pen to paper, the end result is truly an amalgamation of expertise across multiple

disciplines spanning across the globe. Over the years, we have had the pleasure of collaborating with the likes of Zaha Hadid, successive Presidents of the Royal Institute of British Architects (RIBA) including the first-ever female president Ruth Reed, James O’Callaghan, Martha Thorne and Ben Van Berkel. Titans and pioneers, including UNStudio, Foster + Partners, BIG, Buro Happold, Saint-Gobain, Permasteelisa and Dow (to name a few) have regularly contributed to the pages of our Magazine. It is in this spirit of collaboration that we went about conceptualizing the theme of this Summer Edition. The networks and relationships that are required from the concept to fruition of a building envelope are staggering. Indeed, the final façade is a product of multiple inputs and agendas; coupled with increasing expectations of glass as a building material and its performance, a vast number of challenges arise during the process. The glass and façade industries have proven their abilities to adapt, innovate and listen; responding to the requirements of architects and clients through the development of new technologies and products, and through the design and engineering of demanding, unique and ground-breaking projects. This is the story we shall tell…

In this edition, the authors delve into the complex nature of collaboration when designing, engineering and building some of the world’s most innovative structures. Opened by renowned architect James Carpenter, you will be privy to the collaborative efforts and experimental spirit of the modernist vanguards in glass, architecture and façade design…From the client to the architect to the façade engineer to the glass manufacturer, IGS takes you on a journey of collaboration. Our next issue will be published in the Autumn of 2021 where we explore glass facade renovations, retrofitting and adaptive reuse, unraveling the complex nature of the modern retrofit building envelope. From ground-breaking glass technologies to best practice in retrofitting building facades, the industry will speak, once again! Our eternal gratitude goes to those who sacrificed much of their valuable time spending hours preparing articles exclusively for all the beautiful men and women who read IGS - Thank you! Should you wish to address the industry in this edition please feel free to contact us for a more personal and tailored discussion at your earliest convenience. This is IGS, the world’s most popular and beloved glass industry magazine. Nothing more, nothing less.... nothing else! Lewis Wilson Marketing Director and Editor for IGS Magazine

Coming together is a beginning, staying together is progress, and working together is success. – Henry Ford

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CONTENTS IGS SUMMER EDITION 2021 E X E C U T I V E B OA R DRO O M C O M M E N TA RY 9 THE NATURE OF COLLABORATION James Carpenter – Founder, James Carpenter Design Associates (JCDA) James explores the complex nature of collaboration in architecture and glass façade design; from interhuman connections of expertise to relationships with materiality – public space and light are examined through a unique lens. 20

THE YEAR OF GLASS: HISTORY IN THE MAKING Dr. Alicia Durán – President, International Commission on Glass and John M. Parker - Emeritus Professor of Glass Science and Engineering, University of Sheffield A glimpse into the ethereal properties of glass and the collaborative effort from those who built the case for the UN International Year of Glass 2022 - a celebration of its history, current status and future.

ROBOTS AND HUMANS COLLABORATE TO REVOLUTIONIZE ARCHITECTURE Princeton University School of Architecture What do you get when architects, engineers and robots collaborate? The future of beautiful and sustainable architecture.

BUILDING HIGH PERFORMING TEAMS TO DELIVER COMPLEX FAÇADES Neil Dobbs - Head of Façades, Multiplex Discover the process of constructing highly complex façades through exemplary projects that required the creation of high performing teams across multiple disciplines and organizations.

DESIGN FOR TOMORROW’S WORLD: CARBON COLLABORATION EFFORTS IN GLAZING TECHNOLOGY Dr. Kayla Natividad - Architectural Technical Service Engineer, Pilkington North America Kayla examines the drivers of collaboration and innovation in efforts to push towards carbon neutrality and emerging technologies in glass that will contribute to sustainable, energy-efficient buildings of tomorrow.

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71 T R A N S PA R E N T A R C H I T E C T U R A L STRUCTURES 48

HIGHLY EFFICIENT FAÇADES WITH INNOVATIVE SHADING AND LIGHT CONTROL Klaus Reuschle - Project Director, Josef Gartner / Permasteelisa, Robert Matthew Noblett - Partner, Behnisch Architekten and Roman Schieber - Associate Director, Knippers Helbig Delve into the story behind the German-American led façade construction of one of the planets most energy efficient laboratories, featuring the world’s first hydroformed stainless steel sheets used in façade construction.

RCC EKATERINBURG: A MODULAR APPROACH TO CLIMATE AND CULTURE Luke Fox - Senior Executive Partner and Head of Studio, Foster + Partners Luke looks at the cutting-edge design, development, complex fabrication and construction processes that led to the creation and installation of this sustainable, eye-catching and technically challenging façade.

BESPOKE FAÇADE SOLUTIONS FOR 21ST CENTURY ARCHITECTURE Massimiliano Fanzaga - Communication Manager, Permasteelisa 3 buildings and 3 brands have redefined the definition of complex technological façades. From the tallest skyscraper in London to one of the largest regeneration projects in Europe and a fully transparent pavilion, Permasteelisa Group are setting new standards in bespoke design and engineering.

134

GLOBAL CASE STUDIES AND TRENDS GAINING TRACTION 82

EXPLORING EMBODIED CARBON IN BUILDING ENCLOSURES Katherine Chan - Associate and Senior Enclosure Technical Designer and Laura Karnath - Senior Associate and Senior Enclosure Technical Designer, Walter P Moore Katherine and Laura take a deep dive into the future of low-carbon façade design, rallying the A/E/C industry to action in the fight against climate change and citing the untapped potential of building envelopes in reducing carbon emissions.

SILICONE BEHAVIOUR IN BLAST CONDITIONS Valérie Hayez - Global Façade Engineering & Architectural Design Engineer, Jon Kimberlain – Senior Scientist and Sigurd Sitte Senior Technical Service & Development Scientist, High Performance Building Solutions at Dow Dow examines the role of high-performance silicones in mitigating the effects of bomb blasts and the importance of collaboration across industries in developing effective solutions.

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WATER-FILLED GLASS (WFG): NEW OPPORTUNITIES IN GLASS CONSTRUCTION Dr Matyas Gutai - Founder, Water-filled Glass Ltd and Lecturer in Architecture, Loughborough University Matyas gives IGS readers exclusive insights into this pioneering technology that has the potential to revolutionize the performance of glass in buildings, while also driving the agenda of sustainable, energy-efficient design.

114

CAPITAL C: GEOMETRIC OPTIMIZATION OF A FREE-FORM STEEL GRIDSHELL TOWARDS PLANAR QUADRILATERAL GLASS UNITS Koos Fritzsche - Senior Sales Engineer, Octatube, Wouter van der Sluis - Structural Engineer, Goudstikker De Vries, Erik Smits Project Architect and Jack Bakker - Parametric Designer, ZJA Designed by renowned architectural studio ZJA, uncover the technical design and engineering story behind the former Diamond-exchange building’s geometrically complex glass and steel spatial grid shell.

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FLY ME TO THE MOON Georgi Petrov – Associate Director, Christoph Timm – Senior Leader and Daniel Inocente · Senior Designer, Skidmore, Owings & Merrill (SOM) Space: the final frontier - an exploration into the design and engineering limits of deployable habitats on the moon and the technical aspects of glass window design in space with architects SOM.

THE GLASS WORD 134

Intelligent Glass Solutions

“GREAT DISCOVERIES AND IMPROVEMENTS INVARIABLY INVOLVE THE COOPERATION OF MANY MINDS” - Alexander Graham Bell

LEVERAGING EXPERTISE Building High Performing Teams to Deliver Complex Façades Summer 2021

HISTORY IN THE MAKING Towards the UN International Year of Glass 2022

Summer 2021 www.igsmag.com

I, ROBOT Robots and Humans Collaborate to Revolutionize Architecture

THE NATURE OF

COLLABORATION + A true visionary Dr. Hossein Rezai has "THE GLASS WORD" An IPL magazine

Image: 22 Bishopsgate Image courtesy: theimperfecteye / Shutterstock.com Intelligent Glass Solutions is Published by Intelligent Publications Limited (IPL) ISSN: 1742-2396 Publisher: Nick Beaumont Accounts: Jamie Quy Editor: Lewis Wilson

IGS INTERVIEWS DR. HOSSEIN REZAI Dr. Hossein Rezai - Founding Principal and Director, Web Structures In this exclusive interview for this editions “Glass Word”, Hossein shares his thoughts on collaboration, leveraging digital technologies and glass as a building material both now, and in time still to come.

Production Manager: Kath James Director of International Business Network Development: Roland Philip Manager of International Business Network Development: Maria Jasiewicz Marketing Director: Lewis Wilson Page Design Advisor: Arima Regis

Design and Layout in the UK: Simon Smith Intelligent Glass Solutions is a quarterly publication. The annual subscription rates are £79 (UK) , £89 (Ireland & Mainland Europe), & £99 (Rest of the World) Email: nick@intelligentpublications.com

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The entire content of this publication is protected by copyright. All rights reserved. None of the content in this publication can be reproduced, stored or transmitted in any form, without permission, in writing, from the copyright owner. Every effort has been made to ensure the accuracy of the information in this publication, however the publisher does not accept any liability for ommissions or inaccuracies. Authors’ views are not necessarily endorsed by the publisher.

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James Carpenter Founder of James Carpenter Design Associates (JCDA) As designers impacting public space, collaboration with other areas of expertise is one key in harnessing the simultaneously scientific and aesthetic relationships of that opportunity and its contribution to place making. The other is an abiding curiosity which might be described as a collaboration with materials themselves. Page 9

Dr. Alicia Durán President of the International Commission on Glass The UN Year of Glass in 2022 will underline the technological, scientific, economic, historical and artistic role of glass in our societies and emphasize the rich possibilities of developing technologies and their potential for meeting the challenges of a sustainable and fairer society. Page 20

Luke Fox Senior Executive Partner and Head of Studio at Foster and Partners Every facade model features triple glazing with a light grey coating on the glass to reduce heat gain. The opaque portions are clad in durable, micro-ribbed stainless-steel panels, coloured to mimic the tone of copper, in keeping with RCC’s industrial roots, while avoiding that material’s tendency to oxidise and turn green in the open air. The result is a warm, burnished metal facade of repeating, angled modules, cut dramatically with facets of glass. Page 60

Inside th 6

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Laura Karnath Senior Associate and Senior Enclosure Technical Designer at Walter P Moore The last year has shown us that as a global community we must mobilize together to achieve solutions in response to a crisis— we are interconnected, and wide-reaching solutions cannot be achieved in a vacuum. The A/E/C industry along with scientists, academia, and policy makers alike agree that climate change is indeed a crisis. In order to prevent catastrophic warming of 2 degrees or more, we must drastically reduce greenhouse gas emissions across every industry. Page 82

Massimiliano Fanzaga Communication Manager at Permasteelisa Over the years, buildings have become taller and more complex – an ever-evolving process – and that has brought about increasingly complex technological challenges for all parties involved in the creation of such modern megastructures. This evolutionary spiral has affected the sector of curtain wall as well; there has been a shift from units composed of one sheet of glass mounted on an aluminum frame to more complex double and triple “skin” facades using increasingly advanced technologies which now characterise most newly built skyscrapers. Page 71

Dr. Hossein Reza has ‘The Glass Word’ Founding Principal and Director of Web Structures The mantra of “Business-as-usual is not sustainable” is now a clear reality for most of us. The AEC industry is no exception to this tsunami of change. We are not only changing the manner in which we work, with work from home and more remote collaboration, but also are questioning the merits of some of our design and material selection processes by introducing circularity into our work and by squeezing waste and carbon out of them. Page 134

his issue Discover the story behind this dramatic façade with Foster + Partners on Page 60 © Oleg Kovalyuk

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The Nature of Collaboration James Carpenter

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INTRODUCTION Designing and developing glass facades or any other building structure can only be done in collaboration. These are the collaborations between manufacturers, engineers, designers, clients and the construction industry and their goals typically encompass safety, economy and performance. Formal ideas about aesthetics might typically be thought of as one collaboration that exists in tension, or maybe even in opposition to the pragmatic scope of the work being produced.

When described, these collaborative relationships are usually framed by their complexities, and discussion of collaboration typically focuses on celebrating the cooperation needed to overcome the challenges presented by each discipline’s varying agenda. However, there are other aspects of collaboration that I would briefly like to explore here – aspects that privilege the experience of urban places and spaces in-between, above the formal appearance of buildings.

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COLLABORATION – PROFESSIONAL Collaboration is the founding structure of our studio. Since 1979, my studio has consisted of individuals who have studied fine arts, architecture or engineering and we often describe our studio and our ‘discipline’ or ‘space of practice’ as occupying the area framed by these three disciplines, Architecture/Fine Arts/Engineering, thus leaving us a more flexible and agile role from which to deploy our interests. Similarly, we think of our studio as a collaborative partner with several other

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firms with shared aspirations within closely interrelated fields, these being Schlaich Bergermann and Partners for structure and Transsolar for environmental engineering and TriPyramid Structures for manufacturing. These longstanding relationships, going back over 35 years, are of primary importance to our approach to projects as all our initial design work tends to be driven by what many creative designers usually see as secondary – that is performance. Rather than form for forms sake, we tend to try and understand

Migration, gallery film installation, 1975 Photo: ©James Carpenter Collaborating with the University of Washington, which managed this small tributary to the Puget Sound as a site to experiment with various strains of migratory salmon, and with the help of a crew of artist friends, we anchored a series of cameras onto scaffolding erected over the river. The synchronized films captured a fractured but accurate record of the surface of a 60-foot segment of the stream. Each of the films was then projected onto the gallery floor at full scale, creating a 60-foot-long installation, reframing the river’s flow across the gallery floor. One could observe the water flow over the gravel bed of the stream and the salmon moving up from one film frame, through a moment of darkness, into the next film frame and so on for a total of six filmed frames. By editing the timing in post-production, the image of the sky became clearly visible on the surface of the river and was periodically distorted by the image of the salmon, making visible the spatial compression created by the combination of transparency and reflection.

the atmospheric, light, and environmental attributes of a site, tightly framing the conditions and opportunities, and from this set of self-imposed limitations, we seek to find points of inspiration and innovation.

Parallel to this collaboration within our related fields, there exists another level of collaboration between ourselves and the materials we choose to explore and deploy. By this I mean that there exists within the field of materials science, a depth of knowledge, the surface of which is rarely scratched by the architectural and construction trades. My own approach to materials was developed through the trajectory of my education, initially through botany, chemistry and physics which led to architecture at the Rhode Island School of Design, where I gradually transitioned to working in the foundry, machine shops, glass program and eventually film. This hands on investigation of material properties led a few years later to a longstanding relationship with Corning Glass where I worked with Dr. Donald

Stookey, probably the foremost glass/ceramic chemist of the last century. Having many respected partners that bring not only their expertise in their respective fields but their sensibilities and creative energies, expands our studio’s capacity to produce work that reflects a unique sense of place, one with a materiality and relationship to light that connects us to each other and to nature, even in the densest urban environment. Along this line of thinking, we might think of collaboration first as the collaboration we undertake with the materials themselves. Mining a depth of knowledge usually dismissed as unnecessary, we can establish a more essential framework for the design process to become the artistry that defines the best and most lasting civic places. I have often thought of materials as intelligent and glass specifically, as particularly intelligent, in that they carry so much information in their response to the elements (their performance) and that this performance can reveal our profound connection to nature.

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Hong Kong Shanghai Bank, Façade Glass Mock-Up, 1983 Photo: ©JCDA Film and glass led to both an art career in the 1970s and to consulting for Corning, where, with scientist Dr. Donald Stookey, we worked on FotoForm and other photochromic and polychromatic glasses and their possible architectural applications. Working with Stookey radically expanded my understanding of glass as a material. In 1982, Norman Foster of Foster and Partners, became aware of our work developing a glass with louvers, created within the body of the glass by exposing this glass composition to UV light and heat treating the glass, thereby selectively growing crystalline structures within the glass material. We collaborated with Foster & Partners in using this technology on their Hong Kong & Shanghai Bank Tower in Hong Kong – they asked us to produce enough of the material to create a mock-up. Though in that case, the glass was not used, these collaborations and the shift of the artworld in the 1980s led me to explore further opportunities in working with architects and in the burgeoning world of public art.

It was in 1977, while teaching and overseeing the nature lab at RISD, that I was invited to work for six months at Corning Glass. My time working with Dr. Donald Stookey at Corning exposed me to the remarkable technical potential of glass and gave me the confidence to pursue works which challenged the use of glass as a structural material for large scale glass constructions executed as ‘art’ commissions within larger building projects or as integrated 12

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elements within an architectural context (curtain walls, skylights, entries, stairs) This work was the leading edge of the technical and aesthetic advancement of glass as a building material. Many of JCDA’s early completed projects are the primary examples of an exploration demonstrating the compressive strength of glass in complex tensile systems. Much of this work from twenty to twenty-five years ago were the precursors of the work

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Sky Reflector-Net, Fulton Center, New York, NY, 2014 Photo: ©David Sundberg The Sky Reflector-Net is an almost cinematic device that at an urban scale, transposes qualities of nature within the Fulton Center, a transit hub designed by Grimshaw Architects and Arup. Our project here was to develop a primary device that would bring an image of the sky and daylight down into the below ground environment, but this idea was initially founded on how each of the newly linked group of subway lines’ entries might become devices inserting daylight as a wayfinding principle throughout. Our project frames this skylight overhead in an eccentric toroidal cable-net clad with an optical aluminum developed in collaboration with the aluminum manufacturer. The aluminum has a texture which reflects specific levels of color, image and light while the form expands the limited aperture of the skylight. Without the form, your view of the sky would be defined by the skylight aperture and its distance from your eye. The oblique angles of the form’s curvature expand the reflected views of the sky. The typically constrained views of the sky between the tall buildings of Lower Manhattan is folded into the transit and expanded to reveal clouds and sky color over the course of the day.

which we now see used in the Apple stores and for numerous exterior applications. In some respects, Corning did provide the ability to transfer knowledge gained from within their library and from interactions with various researchers there to undertake JCDA's public projects. Underlying this is a vision I have always had which is how can I create works which explore particular events

or characteristics of nature and reframe how we see and experience those events and characteristics within the urban public realm. After establishing my studio, architects would initially work with us for our expertise around glass, its structure and optics, but over time we became partners in design and eventually, the clients came to know us, and we progressively were tasked with playing a more significant role in the larger design

process. This may have been because of our desire to simultaneously think of a project at its most detailed, technically specific scale, and its broadest, experiential scale. For example, we think of the highly technical aspects of glass and its properties, hand in hand with the singular focus on how the experience of light might link us to the unique characteristics of a place, particularly to the nature that exists even in the densest urban environment.

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7 World Trade Center Envelope, New York, NY, 2007 Photo: ©Andreas Keller Seven World Trade Center was the third building to collapse on September 11, 2001. Designed by Skidmore, Owings & Merrill, the new building is comprised of 42 floors of office space that begin 125’ above grade due to the Con Edison transformers occupying large concrete vaults at street level. JCDA, was engaged by Silverstein Properties to collaborate closely with Skidmore Owings and Merrill on the design of the exterior envelope, with a particular focus on the transformer vault cladding at the tower's base which would now be at street level and fronting a new civic space. For the 80-foot-high podium wall, JCDA worked with an industrial filtration manufacturer, using their technology to create a cladding system comprised of two layers of stainlesssteel screen with a 7-inch internal cavity meeting the Con Edison airflow and blast requirements for the electrical transformers. The stainless-steel screen panels are made of triangular prismatic wires orientated vertically and welded in a specified pattern and angle rotation. During the day the outer layer of triangular wire reflects light according to the wires’ orientation. At night, LED lighting between the layers of screen is programmed to both respond to passing pedestrians and to mark the transition of dawn and dusk. Day and night the optimized porosity of the wall accentuates a luminous sense of depth. For the curtain wall, JCDA collaborated with SOM to create a unique ‘linear lap’ glazing detail in which the vision glass overlaps with and floats in front of a fire-rated spandrel clad with a pressed specular texture stainless steel spandrel panel. The sculpted depth of the spandrel panel and floating vision panel creates a volumetric sense of light and a multitude of readings within the building’s façade. The sill of the spandrel consists of a blue stainlesssteel reflector which bounces ambient blue light from the sky up onto the curved reflector. This continually shifting ephemeral color merging with the sky is captured in the façade and enhances urban dwellers’ experiential perception of light. The tower is highly responsive and dynamic, both within the skyline and in immediate proximity, articulating the presence of the sky within this key civic environment.

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COLLABORATION – MATERIAL In my own experience with glass, I have emphasized an understanding of any material in all of its potential permutations – from its variable composition, its structural behavior, to its optical and phenomenological life. Glass reveals the alchemical nature of materiality in that it is transformative, it can exist in a multitude of forms addressing a multitude of functions, and yet if we look at glass in architecture today, it has been reduced almost entirely to a single product, float glass, whose qualities could be described as historically limited or inferior. You could say that consideration of glass materiality in architecture today is mostly secondary to its treatments – lamination, coatings and so on, but the base knowledge of the material in the building industry is for all intents and purposes lost. A direct collaboration with materials is undervalued and largely forgotten. I would argue that material knowledge is the key to meaningful design – a structure designed with a deep material understanding communicates itself directly through its phenomena. Resulting in the streamlining of processes in production, fabrication, and installation, today, design and architecture rely on a fractured or fragmented idea of glass. In order to build efficient structures, architects and designers rely on a narrow range of standard practices while outside of this range, experts have to be brought in. There is certainly a challenge in mastering the complexity of materials and their corresponding techniques, but there are few incentives to put material knowledge at its core. Having been invited over the years to teach a workshop with Professors Sidney Nagel and Heinrich Jaeger, physicists at the University of Chicago, I am routinely reminded of the importance of collaboration outside one’s area of expertise and beyond the purview of pragmatic agenda. By delving into others’ expertise, it becomes easier to approach each project as broadly as possible. Our workshops gave greater depth to the investigation of light, first, broadly as it is reflected, transmitted and absorbed by the materials around us, and second, as a means of probing the physical and chemical properties of matter. Underlying the course was a thorough exploration of light in general and its interaction with the widest range of environments and materials. A critical investigation of light phenomena as they are perceived within various environments was explored as well as the physiological and cultural impact of light. intelligent glass solutions | summer 2021

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Museum at the Gateway Arch West Entry, St. Louis, MO, 2018 Photo: ©Sam Fentress The substantial expansion and renovation to the Museum at the Gateway Arch’s existing structure advances the Museum’s integration into the National Park and the surrounding urban environment, resulting in an intuitive visitor experience from the Park, the Courthouse, and from downtown St. Louis. As part of the Michael Van Valkenburgh Associates' team, and working with Cooper Robertson, JCDA added 45,000 square feet of new exhibition space, and established accessible visitor circulation throughout. More than 100,000 square feet of existing exhibition space was reconfigured by harnessing the site’s natural light, in turn creating a greater connection to Eero Saarinen’s iconic Gateway Arch. As visitors traverse the new landscape bridge over I-44 and approach the Museum, two paths graciously converge and lightly descend to the entry. The additional length allows the paths to be completely accessible, and the gradual slope in turn creates a gentle descent and transition from the landscape to the museum entry, resulting in a seamless pedestrian experience. Within the Entry Plaza, strategic landscaping merges views into and out of the Museum with landscaping in the larger environment, connecting the Park and the Museum. The new West Entry Plaza of the Museum embraces the visitor in an arc of sky and the surrounding landscape, reflected by the diffused scrim of stainless-steel screen walls. The tilt of this reflection references the Arch itself, intuitively leading visitors from the Plaza exterior into the Museum’s glassed-in entry volumes, mediating the transition into the below-ground Museum Arrivals Hall with diffused reflective walls that appear to be carved out of the ground itself and creating a sense of discovery for arriving visitors. As visitors enter, the luminous ceiling leads the eye down to the point of transition into the Saarinen-designed Hall, by following exactly the slope of the landscape. With sensitive planning, innovative materiality, and refined details, every aspect of the Museum’s expansion is now animated by a meaningful vocabulary of light, creating a new space of public engagement previously denied from the local downtown communities, now welcoming all visitors to the site.

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CONCLUSION To have a material’s performance embody the key poetic and aesthetic characteristics of place, collaboration across disciplines is essential. The potential is for design that effortlessly represents the natural world, both the nature that immediately surrounds us but that is hard to register, and the broader sensation of nature extending beyond our view. For example, at every scale of design with glass, there is an opportunity to articulate the presence of light and to unpack and register the dense information stemming from its local and universal interactions. In essence, all materials and their relationships are an opportunity to articulate a more profound collective experience of the world that surrounds us. As designers impacting public space, collaboration with other areas of expertise is one key in harnessing the simultaneously scientific and aesthetic relationships of that opportunity and its contribution to place making. The other is an abiding curiosity which might be described as a collaboration with materials themselves. © Sam Fentress

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James Carpenter has worked at the intersection of architecture, fine art, and engineering for nearly 50 years, advancing a distinctive vision based on the use of natural light as the foundational element of the built environment. Originally studying architecture before concentrating on the fine arts, Carpenter founded the cross-disciplinary design firm James Carpenter Design Associates in 1979 to support the application of these aesthetic principles to large-scale architectural projects. Carpenter’s work is driven by a deep awareness of materiality and craft as a means of enhancing the individual human experience within the built environment. At the intersection of art, engineering and the built environment the firm is recognized for its luminescent artistic sensibility, leveraging the optical properties of materials to deploy the performative aspects of natural light in the public realm. This approach is evident across its practice, including such major cultural projects as the Israel Museum’s expansion and campus renewal project in Jerusalem (2005-2011) and the recently opened expansion of the Museum at the Gateway Arch (2010-2018). Major private projects, including the NYC Nordstrom Flagship façade and public spaces (2014-2019) create a layered, dynamic experience of the built environment through the spatial articulation of glass and light. The firm is also noted for its activations of public spaces, including recently completed designs for New York’s Fulton Street Center, the monumental “Sky Reflector-Net” (2004-2014), and the exterior envelope and lobby of Seven World Trade Center Tower (2001-2006) in New York. Projects such as the University of Chicago’s Midway Crossing (2009-2014), which included landscape and infrastructure linking the college’s north and south campuses, and the Ion (2018-2021), defining the envelope and interior spatial experience for Rice University’s repurposed innovation hub, speak to JCDA’s ability to reintegrate and reanimate the built environment within the urban context. Carpenter has been recognized with numerous national and international awards, including an Academy Award in Architecture from the American Academy of Arts and Letters, the MacArthur Foundation Fellowship, the Smithsonian National Environment Design Award and The Daylight Award from the Villum and Velux Foundations. He holds a degree from the Rhode Island School of Design, and was a Loeb Fellow of Harvard University’s Graduate School of Design and a Mellon Teaching Fellow at the University of Chicago.

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The Year of Gla History in the m

Alicia Durán and John M. Parker

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ass making

lass has been indispensable in advancing contemporary human civilization: in architecture, transport, tableware and packaging. It impacts on cuttingedge sectors: energy, biomedicine, agriculture, information & communication, electronics, aerospace, optics & optoelectronics . Some suggest that we live in The Glass Age and new glass products are regularly developed to address global challenges , contributing to the United Nations’ Sustainable Development Goals. History has many milestones where glass changed life forever. Archaeological finds and historical texts identify glass as an object of luxury, with an important social role in burials and widespread use in jewellery. Ancient writers equated the glassblower’s breath with the wisdom of the philosopher Seneca. Glass blowing, discovered two millennia ago, opened fresh possibilities. Clear vessels stimulated storage, trade and transport. The introduction of moulds facilitated shape control; artisans could make larger, more intricate objects that were collectable, traded and given as diplomatic gifts. The last millennium has swelled the role of glass in our shared heritage: stained glass windows have flooded the interior of sacred spaces with light, highly decorated goblets

Figure 1. The Four Towers, Madrid, Spain

have celebrated the reign of various dynasties, and mosque lamps have communicated a patron’s generosity. Now glass dominates our architectural skyline, solar panels and glass fibre reinforced wind turbines support the energy market, while in the art world it has transcended its classification as a craft material, becoming integrated into the fine arts. These were the arguments which built our case for a United Nations International Year of Glass 2022 (IYoG2022) to celebrate its history, current status and future. The International Commission on Glass (ICG), with the Community of Glass Associations (CGA) and ICOM-Glass broadcast a worldwide presentation of this project in 2020. Support poured in from 1500 Universities and research centres, societies and associations, museums, artists, educators, manufacturers and companies in 80 countries on five continents. Having navigated the disruption caused by a pandemic, the Spanish Ambassador negotiated a draft Resolution outlining our ambitions and steered it through various diplomatic procedures before its formal approval at the UN General Assembly on May 18th, 2021 with 19 countries as co-sponsors . Glass in architecture Cities are hubs for ideas, commerce, culture, science, productivity, social development and much more. With populations projected to reach five billion by 2030, efficient planning and management practices are vital. Common

Figure 2. Low-e and solar control glazings

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issues are congestion, insufficient funds for basic services, a shortage of adequate housing, ageing infra-structure and rising air pollution. The glass and glazing industry offers many solutions. Coated panes and glazing units reduce heating and cooling requirements. Advances will create buildings that are energy neutral or even contribute to the energy grid. So, contemporary residential and commercial architectural design incorporates more and larger window areas. Many options also offer UV protection and contribute to the greening of the transport sector. A recent TNO study quantified the energy savings and CO2 emission reduction potential from such glazing across EU Member States for both 2030 and 2050. As well as the case where all windows use high-performance glazing, it simulated the impact of various window replacement rates. The study drew on sources such as today’s European building stock and performance to define input parameters, the evolution in the energy mix, the penetration of high-performance heating and cooling equipment. The scenarios studied showed that windows with high-performance glazing could deliver 75 MTOE of energy savings in 2030 equivalent to 30% of the buildings’ energy consumption and 67 MTOE in 2050. Corresponding CO2 emission reductions were 94 MMT and 68 MMT. The European Union’s objective is to become the first climate neutral economy by 2050, an

Figure 4. Integrated active multifunctional glazing

ambitious goal requiring drastically reduced energy consumption in buildings even if energy production is decarbonised. Switchable/ electrochromic glazing, glazing-integrated photovoltaics or other novel technologies may be part of the solution. Towards a Circular Economy Sustainable consumption is about promoting resource and energy efficiency. Currently,

natural resource usage is increasing, particularly within Eastern Asia, though associated challenges of air, water and soil pollution are being addressed. Sustainable production aims at “doing more and better with less”. Reducing resource use, degradation and pollution throughout the lifecycle promotes welfare and quality of life for all and creates access to basic services, green and decent jobs. Glass is environmentally friendly. Made from safe, readily available raw materials such as sand, soda ash, and limestone it can be infinitely recycled. As well as using more recycled waste, the glass industry is developing highly efficient melting technologies and seeking paths to carbon-neutral manufacturing . Educating consumers on the concept of a “circular economy” and explaining how lifestyle can be maintained without damaging the planet is necessary before they will commit to the challenges of global change. Accurate information is needed through standards and labels and by engaging in sustainable public procurement.

Figure 3. Antireflective facades. Antireflective tempered glass with high mechanical resistance

intelligent glass solutions | summer 2021

Although often taken for granted, windows allow light into homes and offices while protecting the occupants from harsh weather outside. Today, glass is used in architecture

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Figure 5. Fire-resistance glass AGC

Figure 6. Glass House by Philip Johnson, New Canaan, USA

for both its functionality and its appealing aesthetics. Newly developed products include photochromic and electrochromic materials which can adapt dynamically to sunlight levels, enhancing energy efficiency. Vacuum insulated glazing is new and has improved energy efficiency . Traditional double-pane windows have a noble gas (argon)

between their panes, to reduce heat loss. Now an evacuated space reduces heat transmission further. Glass strength becomes critical with such glazing, since spacers are required to maintain the plane parallel geometry of the two panes and localized stresses are generated near their contact points. The panes must be perfectly sealed to prevent air ingress.

New laminated glasses increase acoustic damping to reduce “noise pollution”. A recent patent uses a viscoelastic acoustic damping layer between the two panes. . Energy saving products, including lowemissivity double glazing in buildings, mineral wool and foam glass for insulation and continuous filament glass fibre composites for

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Figure 7. Transparent living by Santambroglio, Milano

wind turbines, lighter vehicles, compensate several times over during their service life for the energy consumed in production. So, the replacement of single with insulating double-glazed windows saves 60kg CO2/ year compared to 25kg CO2/m2 emissions for manufacture. Glass protagonists in architectural design From Philip Johnson (Connecticut) to Santambrogio (Milan), glass has become the go-to material. The barriers created by floors, ceilings, and walls in a home disappear, and every nook and cranny of the house is visible 24

from elsewhere. Philip Johnson’s Glass House in New Canaan, US is legendary in the History of Architecture. A project for his graduation from Harvard University, the house started from the idea that less is more, inspired by the postulates of Mies van der Rohe (Farnsworth House). A precursor of the modern style and of the use of new materials, it represented an extreme of dematerialization in architecture. Designers Carlo Santambrogio and Ennio Arosio of Italian glass specialists Santambrogio are determined to show the strength and versatility of the material with stunning concept houses made completely of glass.

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The genius of these renowned architects has combined energy efficient glazing with glass insulation to generate transparent glass houses. New functionalities supporting the use of more glass in architecture include reflective facades, antireflective coatings, switchable films permitting transparency and colour control, self-cleaning, fire resistance walls and high mechanical resistance glasses. Cities are becoming safer and more and more transparent. The UN Year of Glass in 2022 will a) underline the technological, scientific, economic, historical and artistic role of glass in our societies, b) emphasize the rich possibilities of developing technologies and their potential

for meeting the challenges of a sustainable and fairer society. It will gather the multi-coloured threads of technology, social history and art through educational programs and museum exhibitions. To maximise the benefits of the one-off opportunity that IYOG2022 brings, glass centred organisations must work together to organise, support and promote a wide range of activities limited solely by their collective imaginations. It will require networking on a local, national and international scale among universities, colleges and schools; R&D centres and industry; museums, collectors and civil society including the government, to everyone’s mutual benefit.

A Durán Dr. Alicia Durán obtained a degree in Physics from the National University of Córdoba in Argentina and a PhD in Physical Sciences from the UAM, developing her professional career at the Institute of Ceramics and Glass of the Spanish Research Council (CSIC). Research Professor of CSIC and the responsible of the GlaSS group (http://glass. icv.csic.es), with more than 250 publications in WOK (H index of 46), she is currently President of the International Commission on Glass (ICG). She received the Phoenix Award from the international glass industry, being named Glass Person of the Year 2019. Now she is leading the International Year of Glass 2022, approved by the GA of United Nations on May 18th 2021.

So, start planning now. Our web site www.iyog2022.org tells more.

Figure 8. Reflective glass facades

J M Parker Dr John Parker, a Cambridge graduate, is a Professor Emeritus at the University of Sheffield where his career was devoted to research on many aspects of glass technology, teaching and student recruitment. Since retiring he is the honorary curator or the Turner Glass Museum and writes a monthly article on glass history for the magazine Glass International. For 25 years he has worked with the International Commission on Glass supporting its many activities.

INTERNATIONAL YEAR OF

GLA 2022

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Robots and humans collaborate to revolutionize architecture

The Office of Communications, Princeton University

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The nearly finished central arch awaits its last brick. Like the entire LightVault structure, the central arch is constructed without any scaffolding or other external supports. The two industrial robots take turns placing a brick and supporting the structure, working from one side to the other. Photo by CREATE Laboratory, Isla Xi Han & Edvard Bruun

wo Princeton researchers, architect Stefana Parascho and engineer Sigrid Adriaenssens, dreamed of using robots to simplify construction, even when building complex forms. “We want to use robots to build beautiful architecture more sustainably,” said Adriaenssens, an associate professor of civil and environmental engineering and the director of the Form Finding Lab. So the professors partnered with architecture and engineering firm Skidmore, Owings and Merrill (SOM) to create a striking and unique installation for the SOM exhibition “Anatomy of Structure” in London last March. They used two industrial robots provided by U.K.-based Global Robots to build a breathtaking vault, 7 feet tall, 12 feet across and 21 feet long, constructed of 338 transparent glass bricks from Poesia Glass Studio.

Professor Stefana Parascho (right) and Isla Xi Han stand beneath a concrete and glass brick prototype built at the Embodied Computation Lab (ECL) in Princeton University’s School of Architecture, in January 2020. Photo by CREATE Laboratory, Shenhan Zhu

Critically, the “LightVault” reduced resource use in two ways: eliminating the need for forms or scaffolding during construction, and improving the vault’s structural efficiency by making it doubly curved, which reduced the amount of material required. This was only possible because of the robots’ strength and precision.

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The robot is placing a new glass brick into the vault structure. The process of construction is exhibited live at Ambika P3 Gallery in London, UK. Photo by Maciej Grzeskowiak, SOM

“I try to find out what robots can do that humans cannot do well,” said Parascho, an assistant professor of architecture at Princeton who developed the idea behind the robotic assembly of the vault. Parascho is the director of CREATE Laboratory Princeton, where CREATE stands for computation and robotics enabling architectural technologies. “My work is not trying to replace human labor by automating it, but to increase the possibilities for architecture by using robots for tasks that humans are rather bad at,” she said. “For example, holding a 3 kilogram [7 pound] brick for seven minutes — without moving, to allow the glue to dry — is very hard for humans to do.” “Robotic construction opens up a number of design and building opportunities where robots complement human work,” said 28

Alessandro Beghini, an associate director and senior structural engineer at SOM, who collaborated on the LightVault. “Robots could be leveraged in places where it would be dangerous for people to work or where access to humans is difficult.” Robots are inherently good at executing precise movements in space, unlike humans, who need guides or support structures to construct complex geometries. This is what inspired the researchers to explore the potential of striking and unexpected shapes. Edvard Bruun, a Ph.D. student in civil and environmental engineering, worked on the implementation of the project. He noted that while human builders would need to double- and triple-check their placement of the blocks, “by leveraging the inherent precision of the robots in navigating 3D space, we could spend more time focusing

intelligent glass solutions | summer 2021

The final, full-scale glass LightVault is displayed at the “Anatomy of Structure: The Future of Art & Architecture” exhibition in London. Photo by CREATE Laboratory, Isla Xi Han & Edvard Bruun

on making the design as efficient as possible, while not getting bogged down in the physical construction challenges typically associated with such a structure.” The team devised a process in which the two robots worked together to assemble the central arch of the vault without any scaffolding or other support. Each robot would place one brick, then hold the structure while the other robot placed the next brick. “Beauty and material or structural efficiency are not mutually exclusive,” said Bruun. “Construction is energy and material intensive. Future global well-being depends on being able to build strong buildings that are efficient with how much material they are built with. Robots have the potential to help us achieve this goal as we develop better ways to utilize them in construction work.”

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Isla Xi Han, a Ph.D. student in Parascho’s lab, was responsible for developing and implementing the robotic fabrication process. “To describe LightVault, I tend to do a mini dance,” she said. “A traditional way to build an arch is two hands coming from opposite ends and meeting in the top middle. Meanwhile, two robotic arms making an arch are rolling hands sweeping from left to right.” After the robots finished constructing the central arch together, they switched to working independently, each building one side of the vault. To ensure the stability of the unfinished structure, the bricks were placed such that each newly placed brick would support the next one. Execution While the team’s intention was clear from the beginning, the implementation was not as straightforward. To build the vault in time for the London display, the team tested each decision with physical prototypes, from small-scale proof-ofconcept ones to full-scale mock-ups. A total of eight structures were built — some in the Embodied Computation Lab in Princeton’s School of Architecture, some at Global Robots, and one at the exhibition space in London. Challenges included finding a connection system that would safely hold the glass bricks in place once assembled, identifying the right construction sequence to ensure the structural integrity of the vault, and controlling the unpredictable movements of the robotic arms so that they would not collide with each other or with completed sections of the structure.

Isla Xi Han, a Ph.D. student in architecture technology who worked on developing the LightVault prototypes, looks at the concrete-and-glass prototype at Princeton’s ECL. Photo by CREATE Laboratory, Shenhan Zhu

“I learned to respect the robots’ ‘personalities’ rather than just telling the poor robots to do things,” said Han. “At one point, the robot’s elbow was constantly hitting part of the existing structure. We ended up taking a step back in the intended design — and equally a step forward in human-robot collaboration — to massage the structure into an asymmetrical shape, to help the robots move more comfortably throughout the construction process. Both parties are happy — it’s a winwin.” Even with so many tests and efforts to predict everything that could go wrong, the team

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One of the construction robots is seen through the double-curved LightVault structure at Ambika P3 Gallery, London. Photo by SOM, Maciej Grzeskowiak

encountered surprises. “The air compressor we bought for the London installation was not strong enough,” said Samantha Walker, a senior structural engineer at SOM. “We ended up sourcing a different, more powerful one at the last minute. You can spend so much time focusing on resolving the complex issues and, in the end, it’s the seemingly obvious ones that can cause the biggest problems.” Another time, after successful prototypes with lighter-weight materials, two tests using the glass bricks “ended in shattered glass all over the lab,” said Parascho. Careful analysis revealed that the robots themselves were deforming a few inches under the weight of the arch. “This made us rethink the entire construction sequence, in order to limit the maximum weight that the robots had to hold,” she said. But the largest challenge was posed by COVID-19. With half the team in London and half stuck back home, construction needed 30

to speed up and be completed in half of the initially planned time. This meant quickly adjusting the design to decrease the number of bricks and coming up with a schedule that would allow for a fast and efficient construction. “In the end, the success of finalizing the vault was topped by the relief of everyone returning home safely,” said Parascho. While the pandemic has impacted the project dramatically — the opening event with over 600 expected guests was cancelled, and the complete team never met in person — “this experience has opened up new and unexpected opportunities,” said Parascho. “The challenges for our field are huge, ranging from how to safely work in a robotics lab to how to run research remotely and finding ways to connect to researchers and other academics. But the current state has also shifted our focus online, which allows and encourages researchers from all over the world to connect more quickly and easily.”

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Construction of the LightVault with industrial robotic arms at Ambika P3 Gallery, London, UK. From left to right: Edvard Bruun (PhD Student at Princeton University) and Arthur Sauvin (Structural Engineer at SOM). Photo by Maciej Grzeskowiak, SOM

There was one silver lining, Bruun said. “We showed that robots are viable tools to work with in a situation where social distancing is an important consideration.” The CREATE Lab is currently working on establishing a remote setup to allow students and researchers to

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LightVault Credits RESEARCH AND IMPLEMENTATION TEAMS CREATE Laboratory Princeton Project Lead: Prof. Dr. Stefana Parascho Project Development: Isla Xi Han, Edvard P. G. Bruun Project Support: Ian Ting, Lisa Ramsburg, Chase Galis, Lukas Fuhrimann Skidmore Owings & Merrill Project Lead: Alessandro Beghini PhD, Michael Cascio, David Horos, Mark Sarkisian, Samantha Walker Project Development: Max Cooper, Stuart Marsh, Masaaki Miki PhD, Matteo Tavano Project Implementation: Dmitri Jajich, Arthur Sauvin Form Finding Lab Princeton Project Lead: Prof. Sigrid Adriaenssens, PhD Project Development: Edvard P. G. Bruun Princeton School of Architecture Project Support: Grey Wartinger, William Tansley Glass & Transparency Research Group - TU Delft Project Consultants: Dr. Faidra Oikonomopoulou, Telesilla Bristogianni Global Robots Ltd Managing Director: Operations Director: Head Engineer: Installation Engineer:

Andy Kirkwood Alex Field Sav Francolino Kevin Amos

MATERIAL SPONSORS Poesia Glass Studio New Pig Corporation

control the robots from home and continue their research through the pandemic. “It has become clear how relevant robots are in today’s world,” said Parascho, “and how they could help in such crises in the future.”

The Princeton research team consists of Stefana Parascho, Sigrid Adriaenssens, Isla Xi Han, Edvard Bruun, Ian Ting and Lisa Ramsburg, with support from Chase Galis, Lukas Fuhrimann, Grey Wartinger and Bill Tansley. SOM’s team includes Alessandro Beghini, Samantha Walker, Michael Cascio, David Horos, Mark Sarkisian, Masaaki Miki, Max Cooper, Stuart Marsh, Matteo Tavano, Dmitri Jajich and Arthur Sauvin. The project was conducted with support from Faidra Oikonomopoulou, Telesilla Bristogianni from Delft University of Technology and sponsorship from Global Robots, Poesia Glass and New Pig Corporation.

About Princeton University School of Architecture The School of Architecture, Princeton’s center of teaching and research in architectural design, urbanism, history and theory, and architectural technologies, provides students with a course of study that reflects on contemporary and emerging issues in architecture. Principal degrees offered by the School include a Bachelor of Arts (A.B.), Master of Architecture (M.Arch), and Doctor of Philosophy (Ph.D.). Students at the School of Architecture benefit from its small size and thorough integration with the University community.

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22 Bishopsgate on the London Skyline Image courtesy of Multiplex

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Building High Performing Teams to Deliver Complex Façades Neil Dobbs, Head of Façades at Multiplex

elivering large and complex construction projects more often than not requires a mix of local and global engineering, material and manufacturing expertise with complicated supply chains. During the last 18 months the construction industry has been tested like never before in modern times following the placing of the country into its first lockdown on 23rd March 2020 and the implementation of Brexit. As an industry we have all risen to this challenge by dusting ourselves off, investigating new ways of working, implementing the necessary infrastructure and continuing to push hard with our project teams to deliver exceptional buildings for our clients.

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Regardless of the political or economic challenges, delivering complex façades in major cities requires collaboration with a diverse supply chain. As a main contractor we are responsible for understanding this supply chain and implementing it on our projects. At our project The Broadway in Westminster the façade is nearing completion and its success has required coordination between specialist façade contractors and material specialists to deliver one of the most interesting but least obvious examples of this coordination, which is the solution to achieving the weathertightness of the façade. The Broadway is a residential scheme delivering 250 high quality units in a prominent location neighbouring Westminster Abbey and the Houses of Parliament. The façade is constructed from a series of repeating precast concrete panels, which are highly insulated and supported from the post-tensioned concrete floor slabs. The precast panels provide two and three storey frames, which encase a prefabricated triple-glazed curtain wall. The challenge, as is often the case, lies in the interface between the two façade systems; the pre-cast concrete panels and the tripleglazed curtain wall. To achieve the architectural intent the creation of a “doughnut” precast panel with factory glazing was not possible, which means that structurally each system is independent and either supported or hung from a post-tensioned concrete floor. The typical approach to sealing a precast concrete façade is to incorporate a double seal between each panel providing robust and maintainable weathertightness. This principle was also adopted at the interface between the precast panels and the glazed curtain walling. To improve buildability of these seals and allow robust checking on site a solution was developed to pre-install a perimeter frame around each opening. This frame was accessible from inside the building, which allowed suitable access to seal and verify the quality of each component, significantly reducing the risk of any rework. The prefabricated curtain wall could be installed into this frame using the tried and tested principles of unitised curtain wall gasket systems. These system principles were established early in the project and developed to ensure ease of 34

Principal Tower Shoreditch Image courtesy of Multiplex

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construction and maintenance. During detailed design and preconstruction the principles were built and tested off-site using a combined precast concrete and curtain walling full scale weather performance test, building the site team’s knowledge of the unique installation techniques and allowing development of a detailed quality plan prior to starting any works on site. These measures were critical in communicating the correct installation method to a team of specialist façade installers that peaked at close to 100 people during the project.

material to seal the joints. The complexity of the support positions of the curtain wall and precast façade resulted in large differential movements between the systems, which had to be accommodated in the design of the joint together with the more usual effects of superstructure deflection and building sway. The sealant had to demonstrate excellent adhesion and compatibility with the many different materials it would come into contact with, such as powder-coated aluminium, anodised aluminium, glass, precast concrete, EPDM membranes and EPDM gaskets.

Whilst the practicalities of these interfaces were resolved and verified offsite, a greater challenge presented itself when selecting the

The scale of the challenge could not be underestimated, with around 55km of joints to be sealed across the six buildings on the

80 Charlotte Street Image courtesy of Multiplex

One Blackfriars under construction Image courtesy of Multiplex

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Broadway prefabricated facade Image courtesy of Multiplex

project. A clear driver from the outset was the desire to simplify as much as possible the application of the sealant via the use of a single product. This approach would benefit future maintenance of the building as well as the construction process. The façades at The Broadway are currently being constructed by precast concrete cladding contractors Decomo (Belgium) and Techrete (Ireland), with the curtain walling being provided by specialist façade contractor Focchi (Italy). Each contractor was responsible for understanding and designing a sealant joint for their respective works, but a deeper collaboration was required to investigate the possibility of using a sealant that could accommodate all of the building movement and material constraints whilst also being acceptable for each contractor’s stringent quality management systems. To progress a solution Multiplex engaged the expertise of Sika to review the constraints against their current product offering. Sika found various products available that solved all of the individual issues; however, a collective solution could not immediately be found.

Broadway Image courtesy of Multiplex

Broadway Install of Precast Image courtesy of Multiplex

Sika widened the search to their global markets and located a sealant formulation developed for use in the United States that had the required movement capability for the project and would likely perform well with all adhesion and compatibility requirements. A programme was put together to bring the product to the European market that involved specific staining and adhesion tests with precast concrete, adhesion and compatibility tests with EPDM gaskets and membranes, 36

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Broadway Facade System Image courtesy of Multiplex

application tests, and the development of three bespoke colours for the project. In the context of a live construction project this presented a huge task against the required programme. The benefits, however, were clear and with engagement from each of the three contractors (Decomo, Techrete and Focchi) the testing programme was gradually completed and within a five-month period the product was CE-marked and certified for use in Europe. The result has been a major success story for the project and whilst the sealant will likely be the last thing discussed when viewing the striking façade at The Broadway, the collaboration and open approach demonstrated by our supply chain has delivered a simple solution for the construction and ongoing maintenance of these buildings.

At One Nine Elms, in Vauxhall, Multiplex is constructing two high-rise residential towers and a new 173-room hotel for the Nine Elms district. The project is being delivered in partnership with Yuanda Europe who are providing unitised façades to both towers and the project’s large podium. The unitised façades are prefabricated in the Yuanda factory and shipped to site where they can be installed safely and quickly using the tried and tested principles of a unitised curtain walling system. As with all high-rise buildings, the façades are complex and must respond to structural movements during and after construction of the towers. The particular challenge at ONE Nine Elms is an external cladding feature that is known as the “flying column,” which is suspended over two metres from the building’s concrete frame. The column

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One Nine Elms Climbing Screen Image courtesy of Multiplex

repeats across each storey of the buildings, which challenges the traditional installation concept of a prefabricated curtain wall. Typically, an installation strategy would allow access safely from the floor slab with easy access to all connections and seals, but this is not possible when the column is suspended so far from the building’s structure.

from the building’s edge. It was important that any solution used would maximise the potential for prefabrication, allowing construction to proceed quickly and efficiently whilst minimising the amount of work required at the edge of the building, which in turn reduced the amount of materials and tools needed there.

In high-rise construction it is important to deliver the façade in a consistent manner, allowing each floor to be completed and made weathertight as the building progresses, which allows the interior fit-out works to progress following the same sequence. To achieve the flying column and maintain construction of the façade on a floor-by-floor basis a unique solution was required.

An extensive development period was undertaken, including digital modelling of the screen system and a full-scale working mock-up of the handling of a façade panel at the DOKA manufacturing facility in Austria. Typically, protection screens rise hydraulically as the building frame progresses to provide protection and access for construction operatives. In this situation, it was important that a lifting device be incorporated in the form of a monorail system that could be raised together with the screen. A separate lifting system would have increased the complication of the screen raising process, which could have put the progression of the floor-by-floor construction sequence at risk. The flying column panels, however, could simply be lifted

Multiplex and Yuanda engaged with DOKA, traditionally a manufacturer of protection screens used for the erection of high-rise concrete frames, to determine if a similar principle could be used to provide both safe access and the ability to handle a prefabricated column panel two metres away 38

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One Nine Elms Image courtesy of Multiplex

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from inside the buildings and easily moved to their installation position by the façade installers whilst suspended from the monorail. Close collaboration was required in the planning and execution of this system and expertise was sought from the concrete frame subcontractors, temporary works designers, façade installers and screen manufacturers to provide a safe and robust solution to construct the flying columns. The result of this can currently be seen appearing to be extruded from beneath the screens on the corners of each tower at One Nine Elms. Constructing highly complex façades in inner city locations requires a great deal of expertise and success depends upon the creation of high performing teams. It is unusual for such expertise to be held within a single organisation and it is therefore important for it to be harnessed early within a project. Often there is a complex and sometimes lengthy path to the simplest solutions requiring close collaboration between designers, main contractors, specialist contractors and material suppliers to ensure success. Neil Dobbs, Head of Façades, Multiplex Neil is Head of Façades at Multiplex where he leads a façade team who oversee a portfolio of projects predominantly in London and Scotland ensuring best practice in design and delivery of complex façades. The façade team at Multiplex is a mix of façade professionals from architectural, engineering and contracting backgrounds engaged in all projects from preconstruction to completion. Neil is responsible for ensuring the team provide technical and operational expertise to clients and projects teams across the portfolio whilst also overseeing all elements of the supply chain from specialist subcontractors to material suppliers.

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IGS Magazine Copywriting Service for Architecture, Glass and Facade Engineering Industries IGS has a passion for creative thinking and highquality content that makes a real impact. Our team of journalists and designers have over 30 years’ experience in publishing, writing and editing content specific to architecture, glass and facade engineering. Our aim is to deliver carefully considered, well executed content that builds your brand profile and connects you with your customers. So, if you’re looking for a creative content provider with a powerful injection of creativity to freshen the global face of your company, IGS Copyrighting Service could be just the tonic you need.

The greatest writing is clear and concise, consequently getting your message across effectively is sometimes easier said than done. Our experienced team of in-house journalists and editors raise your profile with thoughtful and intelligent copy that trumpets your story, hitting the right note every time: 1. Whitepapers 2. Case studies 3. Project write-ups 4. Editorials + Advertorials 5. Blogs 6. Press releases

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Design for Tomorrow's World Carbon collaboration efforts in glazing technology Starting in March, 2010, the Alpen and Serious Energy team built a suspended coated film fabrication line inside the Empire State Building. Over the course of 8 months, the team removed and replaced all 6,514 insulated glass units from the windows (rate of 150 per night), to add a low-e coated suspended film in the center of the units to create a triple pane, low-e coated window Photo by James Hose Jr on Unsplash

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n researching the challenges related to sustainability and energy efficiency in the push towards carbon neutrality, it becomes clear that the solutions are increasingly complex and will require collaboration to accomplish any meaningful progress. New high-performance or net-zero buildings will not be enough to achieve the established targets. Given the approximation that two-thirds of the building area that exists today will still be in place in 2050, restoration and reuse will also be a major focus when we talk about the future of sustainable buildings. Both new building construction and existing building treatments will require step-changes in operational performance and the carbon impacts of the materials used. Design, supply chain, manufacturing, and construction are all critically important and interlinked components to delivering results. Working towards these mutual goals will require education, creative thinking, and coordinated progress to implement new ideas. Importantly, the value proposition and the drivers of these innovations are also more complex now as the analysis goes beyond a simple energy efficiency v. cost calculation. Embodied carbon vs Operational carbon To talk about the future of building design, we must understand what metrics are being used to define targets. Historically, high-performance and sustainable design were discussed through the lens of energy performance. Energy efficiency is a key metric in creating sustainable operable buildings, but this alone is inadequate to capture all the needed gains required to achieve the Paris Agreement 2050 goals. Today this focus has heavily shifted from only focusing on building energy usage to that of energy, carbon, and waste. Since all factors are intertwined, the building's full life cycle and circular economy should be studied. Overall energy usage from material procurement, component processing, manufacturing, transportation, delivery, installation, operating use, and disposal all need to be calculated to understand the full impact of carbon and energy and the actual impact the project has on the environment. In simpler terms, these components are being further defined and measured through the analysis of operational carbon and embodied carbon. Operational carbon refers to the sum of carbon dioxide and other global warming 42

Installation of a Winsert unit into an existing opening. Image courtesy of Alpen High Performance Products

gases emitted during the in-use phase of a building. These emissions are generally referred to as greenhouse gases (GHG) and quantified by their Global Warming Potential (GWP). Operational carbon is a summation of emissions from all energy sources used to keep our buildings warmed, cooled, lighted, and powered. Throughout the rest of the article, operational carbon and energy efficiency will be used interchangeably as it is unlikely to have one without the other. Embodied carbon, on the other hand, is the total amount of emissions from energy sources during the sourcing, manufacturing, and transportation of building materials to the construction site. GWP of construction materials is reported in material Environmental Product

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Declarations (EPD) and is used to quantify the initial preoccupancy environmental impacts of a structure. Building restoration can have significant impacts on minimizing embodied carbon through the reuse of existing materials and minimal introduction of new building elements. Policies are being put in place at all levels of government to regulate operational and embodied carbon in new and existing buildings. An example of operational carbon legislation is New York’s Local Law 97 which requires a 40% carbon reduction by 2030 for commercial buildings larger than 2,323 m2 (25,000 ft2). Buildings that fall within the scope and do not comply will be fined starting as early as 2024. Although it’s only implemented

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for existing buildings, once a new construction project is completed and occupied it falls under the existing building category. From an embodied carbon approach, California has implemented a Buy Clean Act (AB262) which defines a GWP limit for specific building materials to limit the amount of embodied carbon that goes into new projects. The key difference in these laws as compared to other types of building regulations comes down to three significant differences. First, the laws are becoming more performance-based versus prescriptive-based. This drives the demand for solutions that measurably reduce energy efficiency and perform achieve targeted goals. Second, these laws are targeting existing buildings, rather than just new construction or when building upgrades occur, and are

time-based to achieve results. Lastly, the impact of energy usage is being measured for both the building operating and embodied carbon impacts. Together, these new laws will start driving down measured carbon usage in the construction and operations of buildings. Drivers for Collaboration So, what are the key challenges that drive the need for collaboration? Given the design and structure of the industry and pending regulatory pressures on existing and new buildings, there certainly appears to be great opportunities for innovation and development of higher performance products. However, the glass and glazing world is complex with several interconnected sectors. The technology for high performance, dynamic, and robust solutions to these performance figures has

Lightweight solution - ~25ft2 unit weighing less than 40 lbs. Image courtesy of Alpen High Performance Products

been around for some time and market availability is being driven by efforts from all parts of the industry. 1. Project Cost: To stay within budget or minimize project cost, glazing/fenestration is often designed to be code compliant but not designed to dramatically exceed code. To push higher performance products, the project cost versus the full carbon impacts needs to be understood to create a compelling use case. First, it takes education on available solutions and building owner interest to start the adoption cycle. With the adoption of high-performance glazing components comes market demand. With demand comes improvements in fabrication capabilities and increase market availability. With increased market availability comes a cost reduction. With cost reduction comes more widespread adoption of high-performance glazing components. It’s the (market) circle of life. But it takes continuous product development from manufacturers, adoption, and promotion of new products from fabricators, and willingness for project teams to design past code requirements to optimize building sustainability. Most of all it takes innovation from all sides.

Installation of a Winsert Plus into the Empire State Building installation. Image courtesy of Alpen High Performance Products

2. Design Impacts: In addition to the adoption of new technology, design impacts can significantly drive cost and results. For example, when moving from double to triple glaze the impacts stretch further than the intelligent glass solutions | summer 2021

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addition of a glass layer. The movement to a triple IGU results in a thicker profile and larger extrusions. These changes in profile result in heavier design loads and increased embodied carbon from additional glazing materials. Moving to heavy glass units also requires new fabrication equipment and methodologies on the production side. The heavier thicker window can also impact overall window size and design, especially in operable windows. These complexities impact cost, energy efficiency, and embodied carbon demand. 3. Retrofit Limitations: While the first two design hurdles apply to all construction projects, measures to enhance existing building performance can be even more limited. This can be due to several factors, such as a. National Historic registration limits on construction, b. Limitations of existing structural load capabilities, c. Push to reuse existing building elements, such as sash and framing, to minimize additional embodied carbon impacts

Side view of thin triple showing thin center glass and relatively slim cavities. Image courtesy of Alpen High Performance Products

US adoption of double glaze low-e courtesy of LBNL report

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Traditional treatments for existing buildings generally fall within two categories: 1. Adding secondary glazing to existing windows, or 2. Installing new higher performing replacement windows. While adding secondary glazing has a reduced impact on a building's embodied carbon it doesn’t typically achieve the highest operating performance (as compared to full replacement). The typical addition of a clear lite or introduction of a monolithic Low-E

Thin quad glazed units. Image courtesy of Alpen High Performance Products

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Installation of ¼” VIG at Milwaukee County War Memorial. Courtesy of Neal Vogel from Restoric

product without a hermetic seal most times will not bring performance up to modern new construction standard requirements. Alternatively, fully replacing existing windows with new, high-performance, glazing will have a significant impact on the operational performance of the structure. In doing so, however, you may require the introduction of a double-glazed system where there was not one previously. This can introduce significant embodied carbon from not only the glass itself but modifications to sash and framing.

New concepts and collaboration The thin triple is one example of a collaborative effort that is starting to come to market. This concept isn’t new as the patent technology was created in 1991 via a group with Steve Selkowitz from LBNL. However, there are now several different market sectors and drivers helping support this technology adoption. The concept can help ease triple glazed units (TGU) into the market by creating a TGU that would fit into the existing DGU (double glazed unit) form factor. This allows you to upgrade the energy efficiency of the window

without fundamentally changing the design and component elements. This allows you to maintain the same DGU extrusions and window design and only change the glazing components. As the definitions of sustainability and carbon usage v. energy efficiency have become more complex, the potential gains and benefits of this thin triple product become more interesting as well. The primary focus of easing the adoption of a TGU into the DGU market remains clear but there are some additional benefits to

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now consider. For one, the embodied carbon impact scales with glass weight so using a thinner and lighter glass component creates less GWP emissions due to the lower weight. Therefore, the thin TGU design improves both the operational efficiency while also reducing the embodied carbon impact of the window design. The thinner glazing component also utilizes narrower extrusions and framing channels, which would also result in lower material demands (lower embodied carbon) from the framing design. The thinner and lighter-weight materials also potentially reduce the structural elements to support the building skin, which also has the potential to further reduce the embodied carbon impacts of the structural design. Finally, the thin triple can also be used to upgrade existing buildings where there is an outdated DGU design. Not only does

this type of product then dramatically improve the operating efficiency, but also greatly reduces the embodied carbon impacts by enabling material reuse of the existing framing. For the thin triple to be a reality, this takes an orchestrated effort from a wide variety of partners on the supply chain. NSG Pilkington has made continuous strides to bring lightweight and thin technologies to the market. The manufacturing, handling, logistics, and size components are all critical to having the right building blocks in place to create this product. NSG Pilkington has also been an innovator in such glazing technologies as vacuum insulated glazing (VIG), buildingintegrated photovoltaics (BIPV), and other technologies which help support these collaborative and performance-boosting

Thin triple unit. Image courtesy of Alpen High Performance Products

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solutions. Quanex has helped develop spacers and materials to help create and frame these new high-performance and transitional edge concepts. Alpen High Performance Products – a leader in high-performance glazing – has stirred interest in using thin glass both for the thin triple concept as well as for ultra-lightweight, high-performance secondary interior window inserts. Handling, fabrication, and manufacturing of these new high-performance products are critical in understanding the viability of thin glass use. Lawrence Berkley National Lab (LBNL) has for years been highlighting the use of lightweight, thin, non-structural layers for significant improvements in thermal performance and is now helping connect all the potential partners in this supply chain and help identify potential barriers or weak points in the supply chain that need development. Incentives for the adoption of new high-performance products have been implemented already by the California Advanced Homes Program (CAHP) and the Northwest Energy Efficiency Alliance (NEEA) which further help drive adoption.

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The 2010-2012 ‘re-manufacturing’ at the Empire State Building was set up on the Fifth Floor where we cut apart, cleaned and re-used the 1990 1/8” tempered inner and outer lights – to be reassembled as R-7 (E, S, and W) and R-8 North “Triple” Alpen glass with directionally “tuned” suspended coated heat mirror film.

window transformation space. Together, the group goal will be to expand these proven strategies and technologies to expand the use of these concepts. Initial efforts will focus on regional programs to help promote highly insulating windows (~R5) for residential markets, both new and retrofit, but the program can promote a wide variety of technologies that contribute to the emerging carbon savings goals. Conclusion The future of sustainable design is dependent on innovation and collaboration from all sectors of the building, construction, and design industry. As progress is made in technology developments a push for adoption is equally, if not more important. Remember those code requirements are minimum requirements; if we want to design for tomorrow’s world, we shouldn’t use today's requirements as a threshold for optimum performance. There is room for development, adoption, and growth for everyone involved.

Dr. Kayla Natividad Dr. Kayla Natividad, WELL AP, LEED Green Associate has been with Pilkington North America as an Architectural Technical Service Engineer since 2016. She received her PhD in civil engineering with a focus in structures and research in glass design. Since joining Pilkington North America, a major focus of her work has been directed towards sustainability and green building initiatives. She is an active member of many industry organizations and participates in codes and standards development for North America. Kayla has and continues to promote green building through education and advocacy of glass technology.

Image courtesy of NSG Pilkington

The thin triple is a great example of innovation in the glazing world, but many other emerging glazing technologies such as vacuum insulated glazing (VIG), dynamic glazing, and power generating glazing are also making similar progress with collaborative development efforts. Once this full value creation is understood in terms of operational carbon, embodied carbon, design, project impact, and occupant benefits, these new technologies start to highlight the real potential of innovation to create solutions for the climate crisis.

Next steps Given the breadth of available technology for high-performance and/or lower carbon impact designs as well as the emerging regulatory demands on operational and embodied carbon impacts, it seems that the time is right for expanded efforts and collaboration to help commercialize these ideas. One such concept is the Partnership for Advanced Window Solution (PAWS) which is a public and private partnership made of a variety of volunteers from stakeholders in this climate change and intelligent glass solutions | summer 2021

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Highly efficient fa with innovative sh and light control

Harvard University: SEC Complex of the John A. Paulson School of Engineering

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açades hading

Klaus Reuschle, Project Director, Josef Gartner / Permasteelisa Robert Matthew Noblett, Partner, Behnisch Architekten Roman Schieber, Associate Director, Knippers Helbig All photos by Brad Feinknopf

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n autumn 2021, Harvard University plans to open its new Science and Engineering Complex SEC. The new building, with its four different façade types, has been clad with highly efficient steel and aluminium façades which are nested within each other. The solar heat input is regulated by geometrically optimised shading with the world’s first hydroformed stainless steel sheets used in façade construction. Light screens direct the daylight into the interior rooms. The Science and Engineering Complex (SEC) on the Allston Campus, which extends 150 metres along Western Avenue in Boston, is the largest new building at Harvard University in recent decades. It will accommodate various fields of engineering sciences on a floor space of around 50,000 square metres. With a variety of stateof-the-art labs, training and seminar rooms, the SEC provides the highest standards for scientific work. German-American cooperation for one of the most energy-efficient laboratory buildings in the world As one of the world´s healthiest and most energy-efficient laboratory buildings with LEED Platinum certification, the SEC's façade achieves a heat transfer coefficient of less than 0.9 W/ m2K. Unwanted solar heat gain is reduced by 45 percent across the main façade. The external shading also allows the CO2 emissions from the gray energy to be amortized after only about 12 years. The fixed sunshade screen is geometrically calibrated to lower peak cooling loads by 65 percent. The innovative building was designed by Behnisch Architekten, who, together with Knippers Helbig, developed concepts for different façade types in an early phase of the project. In a collaborative process, together with Harvard University as the Client, Turner Construction as the General Contractor and façade specialist Josef Gartner - a division of Permasteelisa North America Corp., the individual façade types have been refined. It was the smooth cross-border communication between these parties, characterized by a strong German-American component, that made it possible to realize numerous new technical developments. 50

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Three building volumes around two light-flooded atria spaces The eight-storey building is divided into three portions arranged around two light-flooded atria. Highly transparent glass ribbon windows in the base open the building up to the outside environment. Five glass entrance facades, cut into the building complex, extend over two floors and give structure to the building. The two-story, transparent base houses generally accessible spaces such as the library and a café, as well as classrooms and lounges. Deep overhangs combined with perforated metal lightshelves shade these areas and direct daylight deep into the interior of the building. Above this transparent base, the four-story research boxes seem to virtually float, lending the building a special lightness. Customized stainless steel sheets block the solar heat in summer and direct daylight inwards The labs are arranged in these research boxes, which are clad with specially allocated stainless steel sheets for shading. Not only do they convey a uniform appearance, they also shield the rooms from solar heat in the warmer months, while allowing solar radiation in winter when the sun is lower, thus reducing the cooling and heating load. To achieve this, intelligent glass solutions | summer 2021

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the modules were dimensioned according to orientation and angle of the sun. At the same time, they are arranged to reflect daylight inward and provide large viewing openings. On the terraced south side, garden facades open the complex to the park. Vertically, the six above-ground levels and the two below-ground levels are connected by a central atrium that provides all floors with daylight and fresh air. This atrium is the communicative center and can also be used for events. In addition, there are smaller atria in individual areas of the building. 52

Almost all rooms with workstations are oriented towards the façade and mediate between inside and outside. All offices and meeting rooms have operable windows that allow fresh air to cascade deep into the building. Lounge zones that open up over several floors connect the individual laboratory areas with each other and serve as meeting spaces and lounging areas. Sustainable architecture and building materials without harmful chemicals The building, which has been certified according to LEED Platinum and awarded the

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"Living Building Challenge Petal Certification in Materials, Beauty and Equity" by the International Living Future Institute, reduces CO2 emissions by up to 50 percent compared with comparable buildings. A key factor here is the customized façade, which is individually tailored to each compass direction. Around 16,500 square meters of green roof surfaces provide a pleasant climate in the immediate vicinity of the building and offer occupants direct views of the greenery. The façades also allow for natural air supply and laboratory ventilation. In a detailed study, the optimal ventilation rate for each area of the building

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was determined beforehand in order to reduce ventilation by up to one third. In cooperation with Harvard University and Turner Construction, Behnisch Architekten tested all building materials for their chemical composition in order to make the building healthier for its users. The university aims to be climate-neutral by 2026 and free of fossil fuels by 2050. A milestone towards this goal is the SEC with its sustainable architecture, energyefficient façades and building materials that are free of harmful chemicals.

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Close cooperation in the façade engineering process Approximately one year after the architectural and preliminary technical development of the façades by Behnisch Architekten and Knippers Helbig, contract award discussions began. After the completion of this award phase, the following three-month Design Assist phase was dedicated to the further development of the individual façade types in collaboration with façade contractor Gartner, Turner Construction, and Harvard University. During this time, the wide span, south-facing, fully glazed atrium façade was completely redesigned to meet the Client's budgetary requirements. The external screen of the main façade included the integration of springs into the tension rod structure to reduce the pre-stressing level of the structure. In addition, material and fabrication options were discussed. In the end, hydroformed stainless steel panels with a high material efficiency were selected, which were compelling with their low gray energy and technical aesthetics. These stainless steel panels have a delicate, filigree materiality that almost approaches the lightness of textile fabric. Joint project development meetings took place every two weeks in two-day workshops partly in Boston, partly in Gundelfingen, Bavaria, and partly virtually. In the end, numerous smallscale mock-ups and large-scale prototype façades were built to finalize individual details and material options. Only then did works and installation planning, process planning, etc. begin. Different types of façades with operable modules The German façade specialist Gartner has then manufactured the SEC building envelope using many different types of façades, including a unitized aluminium façade, steel stick-system façades, suspended steel stick-system façades, highly insulated sheet metal panels, stainless steel shading modules, deep-drawn stainless steel sheets and operable hinged and louvre windows. The relatively small components with several interfaces are also nested within each other and are structurally demanding. Since Behnisch Architects in Boston and Harvard University wanted to save as much energy as possible, all façades had to incorporate operable vents for natural ventilation and they had to meet stringent thermal requirements. The façade was 54

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therefore designed in a way that optimizes the energy balance and maximizes natural light. The building envelope shields the interior from solar radiation in the warmer months, while letting the sun in during the winter, reducing cooling and heating loads. Filigree steel façades with hydroformed stainless steel sheets The research boxes were clad with a 7,600 square metre steel screen façade and tripleglazed insulating glass with a solar control and heat insulation coating. Stainless steel shades are suspended from this stick-system façade which features a dimension between axes of 1600 mm. As suggested by Gartner, these deep-drawn stainless steel sheets, which were continuously refined during the design phase to improve shading and lighting, replace traditionally bent and welded sheets. intelligent glass solutions | summer 2021

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The approximately 12,900 stainless steel sheets measuring 600 x 600 mm were pressed into a mold using water pressure, as the complex geometries cannot be produced in a traditional sheet metal manufacturing process. Hydroforming, which is common in the production of components for the food and automotive industries, was used here for the first time in façade construction. This world's first hydroformed façade system offers architects more design options, including organic shapes. Numerous studies, rapid prototyping techniques, the use of innovative simulation software from industrial design such as CATIA helped to determine the shape of the panels, their optimal thickness and their production method. Solar radiation and glare protection could also be optimised by hydroforming. Since the complex geometries could not be produced in one go, the sheets had to be annealed and pressed for a second time. They were then cut to size using a 3D laser robot and were given several hundred holes per sheet. This perforation reduces the contrast of light incidence and shading to a comfortable level. Finally, the sheets were sandblasted to achieve a matte finish. The size and shape of the shading units are precisely matched to their respective positions on the façade. At the same time, occupants can still look out through the perforated panels. The pre-stressed tension rod façade is also a unique feature of this building, as the sheets and tension rods are stretched over up to 4.5 storeys. Tension rods with a diameter of 16 mm have been designed and manufactured especially for this project. 570 steel springs with a diameter of 120 mm, each of which was pretensioned to 760 kg on the construction site, tension the rods and provide uniform stability even with large temperature fluctuations. They are attached to large steel cantilevers, which are arranged at the top and bottom around the building outline and position the stainless steel sheets in front of the actual steel glass façade like a double skin façade. Unitized aluminium façades with structural shading panels made of up to 25.5 m long perforated sheets The garden façades of the two lower floors as well as the south-facing terraced parts of the building consist of a 9,100 sqm aluminium façade, which is set back for the terraces, while intelligent glass solutions | summer 2021

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the south side features curtain-type shading panels attached to steel cantilevers. For the floor-to-ceiling glazing of the ribbon window, two out of three modules are fully glazed, while the third unit is opaque. Every third unit is equipped with operable top-hung windows. The 20 m high and 23 m wide central atrium and the 17 m high and 14 m wide western atrium are clad with 3,000 square meter atrium facades suspended by a steel tension rod system with dimension between axes of 3657 mm. Since they cannot withstand the wind loads, the shading panels had to be designed as structural panels to reinforce the very filigree façade (construction depth of 50 mm). The 1.6 m wide and up to 25.5 m long shading panels consist of 5 mm thick perforated stainless steel sheets. The five entrance façades extend over two storeys and cover a total of 1,000 square metres. This stick-system steel façade has a dimension between axes of 1,600 mm with a fully glazed vestibule on the room side.

Robert Matthew Noblett (Matt Noblett), NCARB, AIA is Partner of Behnisch Architekten, Boston. Born in 1971 in Cleveland, Ohio, he received his Bachelor of Science in Architectural Studies in 1994 from the University of Illinois at Urbana-Champaign and a Master of Architecture in 1997 at the Massachusetts Institute of Technology in Cambridge, MA. Prior to Behnisch Architekten Matt worked for nine years at Rafael Viñoly Architects PC in New York, NY, where he served as project manager for large-scale, complex projects in Boston San Francisco, and Chicago among others. In 2006, he joined Behnisch Architekten, where he has been leading as Partner since 2009. Matt has served as Partner-in-Charge for many projects and competitions including the Harvard Allston Science Complex, the John and Frances Angelos Law Center at the University of Baltimore, the Amherst College Science Center, the University of Baltimore Langsdale Library Renovation and Extension, the School of Business Administration at Portland State University, and the Artists for Humanity Epicenter expansion in Boston. Matt has also taught at institutions of higher education in Boston, and has lectured extensively worldwide on topics pertaining to sustainable architecture and design excellence.

For natural ventilation, 480 windows have been integrated into the façades, 60 of which motorised and 420 to be opened by hand crank. There are also 52 motorised louvre windows. The motorised windows also serve as smoke and heat extraction vents (SHEVS).

Construction Project Signboard Owner: Architect: General Contractor: Facade Consultant: Facade:

President and Fellows of Harvard College Behnisch Architekten, Boston Turner Construction, Boston Knippers Helbig, Stuttgart Josef Gartner USA - a division of Permasteelisa North America Corp.

Films about the new SEC on Youtube A peek inside the new SEC https://www.youtube.com/watch?v=a2kIFoa5Iuc The Harvard Science & Engineering Complex https://www.youtube.com/watch?v=KyBxPWdsaVE

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Klaus Reuschle, Project Director, Josef Gartner USA a division of Permasteelisa North America Klaus Reuschle joined Gartner in Germany in 2008 and became Project Director for Gartner USA in 2017. He holds a degree in Project Management in Construction from the University of Applied Sciences Biberach a.d.Riss, Germany. Klaus has been in the façade industry for 15 years.

Roman Schieber, Associate Director, Knippers Helbig Roman joined Knippers Helbig in 2007; since 2016 he has been a member of the board of directors. As both an Architect and Certified Facades Engineer, Roman leads the Knippers Helbig facades team in New York City and Stuttgart.

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Shaping sustainable futures

www.arup.com intelligent glass solutions | summer 2021

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RCC Ekat A modular approach to climate and culture

The practice’s first office building in Russia, the RCC (Russian Copper Company) Headquarters in Ekaterinburg, reimagines the conventional cellular workplace to set new standards in quality, comfort and flexibility. The 15-storey building’s innovative modular office units are enveloped in an advanced, triangulated enclosure that is highly energy efficient and also provides a distinctive architectural symbol for the organisation.

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terinburg: The crown of the building intelligently integrates RCC’s new logo – a gesture made possible by the company’s graphic rebranding having evolved from the architecture itself. The article looks at the innovative design development and complex fabrication and construction processes that led to the creation and installation of this sustainable, eye-catching and technically challenging facade. © Oleg Kovalyuk

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Designing from the inside-out The starting point for the office floors was to rethink common ideas about what a generic headquarters can be and provide a more focused and bespoke approach. This was led by the Russian company’s request to avoid the large-scale and open-plan workspaces of many conventional developments in favour of more tight-knit collaborative spaces and intimate, domestic-scaled offices. (In fact, the word for headquarters in Russian ‘штаб-квартира’ can be literally translated as a ‘house for staff’.)

This approach evolved from numerous collaborative reviews with the client and indepth studies of their working practices and preferences. The design team carried out an analysis of the client’s operations and ways of working, which concluded that a combination of focused offices, suitable for teams of four and six people, would best serve their operations. The challenge was then to find an arrangement that would allow all workspaces to have an optimal and uniform distribution of natural light while also enabling rapid construction.

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These two basic typologies – the four- and six-person office units – were therefore at the heart of the innovative modular system that underpins the design, placing the experience of the staff at the centre of the architectural approach of the entire building. The team developed a two-storey module from these units, with the smaller four-person workspaces stacked on top of the larger sixperson ones. The modules are then arranged in rows on either side of a central hallway, which

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functions as a breakout space, with lounge seating and views of the city through the fully glazed end wall. A bespoke Y-shaped staircase anchors this central space and provides access to the mezzanines that run alongside the upper units.

Furthering the design’s modular approach, six of these two-storey floor modules were then stacked vertically to generate the building’s primary office levels. Developed in conjunction with the practice’s in-house engineering teams,

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the building’s modular layout is expressed externally through the double-height facade units that clads each module. The design of the facade is, therefore, derived directly from the client’s specific ways of working, with the two-storey elements reflecting the tightly integrated and humanscaled workspaces that repeat up the building. With this user-focused foundation, the design team then developed the facade into a visually rich, materially complex and energy-efficient detailed design, in response to the unique context and climate of Ekaterinburg. 64

Climatic context and response The city of Ekaterinburg is known for its short, blisteringly hot summers and long, freezing winters, not to mention the significant rain that falls throughout the year. The annual temperature range is between 30 degrees Celsius in the summer and minus 30 degrees Celsius in the winter. This brings a particular set of challenges, as the facade had to be designed to perform well at either temperature extreme. It also had to prioritise abundant natural light due to the normally overcast conditions throughout the year, but without blinding occupants during the sunny summer months.

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As such, the distribution of solid and glazed areas across the facade is a careful balancing act. The team started out with a pair of windows for each two-storey module, one for the upper four-person office, and another for the lower six-person office. These were scaled to provide a 1:1 ratio between the opaque wall and transparent glass across the whole module; this would provide an optimal equilibrium between light and shade and minimize heat loss through glazing. However, simply punching bright central windows in the dark walls would produce

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uncomfortable levels of contrast and glare, even in the usually overcast conditions of Ekaterinburg. Working with the practice’s Specialist Modelling Group, the team began to explore different options for a facade with a 1:1 glass and wall ratio, including one successful iteration where the entire height of the twostorey facade module is divided vertically, with glazing on one side and solid wall on the other. In this option, the external wall was then tilted outwards, and the angled form worked exceptionally well by bouncing natural light onto the opaque portion of the facade and spreading it more evenly through the interior. intelligent glass solutions | summer 2021

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This reduced the contrast between wall and glazed portions and provided the added benefit of directing the window area out to views of the city, acting like a bay window. Furthering this design in response to sun-path analysis, the direction of the divide between solid and glazing evolved from a vertical line to a diagonal one. The upper of the two resultant triangles was set as opaque, while the lower was glazed. This diagonal design, with its broadest areas of glazing at the units’ lower levels, allows in more low-level sun during the winter months, while protecting against the heat and glare of high, direct sunlight during the summer. Additionally, the opaque portions of the facade were capped with a sloped canopy to further minimise solar gain during the summer. Every facade model features triple glazing with a light grey coating on the glass to reduce heat gain. The opaque portions are clad in durable, micro-ribbed stainless-steel panels, coloured to mimic the tone of copper, in keeping with RCC’s industrial roots, while avoiding that material’s tendency to oxidise and turn green in the open 66

air. The result is a warm, burnished metal facade of repeating, angled modules, cut dramatically with facets of glass. In total, 160 facade modules envelope the entire building. The standard two-storey, ten-metreby-six-metre module, weighing 8,500 tonnes, is used across the majority of the tower, while the lower-most modules, wrapping the building’s double-height ground-floor lobby, are slightly taller, measuring 12 metres. Such scale and complexity meant that construction and installation of the facade posed the design and contractor teams a number of challenges, both geographic and operational, which catalysed further innovation and a series of ‘firsts-of-its-kind’ in the Russian building industry. Construction challenges Given the intricate geometry and composition of the repeating facade panel, there were several mock-ups built to test its performance, both in factory conditions and then on-site. To certify the bespoke facade for air tightness, fire rating, water tightness and acoustics, the

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cladding consultant produced a performance mock-up that consisted of two full facade modules and two quarter modules. This was then rigorously tested to assess the design, engineering and construction details such as the material junctions. The modules were prefabricated in a purposedbuilt factory in Russia, before being shipped to Bielefeld, Germany, where three main tests were carried out to assess water and air tightness. The facade modules were built onto the back of a sealed chamber, so the assessors could amend the pressure and record the performance of the facade modules’ cladding and structure during the dramatic warping and deflections caused by the pressure changes. The team were pleased to witness the modules pass with flying colours. © Oleg Kovalyuk

Image courtesy of Foster + Partners

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Typical South Module Presentation drawing - Typical cladding module © Foster + Partners

Due to the import restrictions in Russia, the fabrication and assembly of the facade had to be carried out locally. The design team and our local collaborators together rose to the challenge and developed dedicated manufacturing units to make the unique panels for the building. Using specialised 3D plasma cutters and robotic welding arms for the stainless steel, the complex geometrical junctions of the frame were carefully fabricated to a tolerance of three microns per metre in a bespoke factory unit. The frame was then transported to an on-site hanger, where the external stainless-steel panels and glazing were affixed, and the completed module was installed onto the building. The demanding testing and prototyping enabled the design team to continuously refine and develop the facade throughout the design 68

and construction process. The result is a one-ofa-kind integrated modular facade that performs for the building’s users, responds to the region’s climate, and offers a new architectural symbol for RCC in Ekaterinburg. The project exemplifies the practice’s commitment to technical and material innovation, energy-efficient and sustainable design and people-centric spatial and environmental architecture. The integrated team developed a holistic vision that is rooted in the way RCC operates as an organisation and prioritised the wellbeing of the company’s staff. Through this process, the project has also revolutionised and rehabilitated a traditional idea of cellular office working and created a flexible modular system that responds to the changing patterns of work and seasonal cycles of nature.

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Image courtesy of Foster + Partners

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Presentation drawing - West elevation © Foster + Partners

Luke Fox, Senior Executive Partner and Head of Studio at Foster + Partners Luke Fox is a head of studio at the practice and part of the Design Board. He leads a team of designers in London, Hong Kong and Beijing on a wide range of international projects. He is originally from Sydney, Australia and studied architecture at the University of Sydney. After graduating he worked in New York and he joined Foster + Partners in 1998. Luke has worked on many significant projects varying from infrastructure and offices to hospitality and residential. His recent schemes include new offices for Chinese ecommerce giant Alibaba, in Shanghai; Jeddah Metro, where the practice was appointed to develop the architectural vision for Jeddah’s city-wide public transport plan; Sydney Metro’s new station designs; the design of four Haramain High Speed Rail stations in Saudi Arabia, connecting the cities of Makkah, Madinah, Jeddah and the developing King Abdullah Economic City (KAEC); Lusail Stadium in Qatar, the iconic venue for the 2022 World Cup; Murray Hotel, a new luxury hotel in Central Hong Kong; a new Four Seasons Hotel in the heart of Makkah for Jabal Omar; a new Headquarters for RMK in Russia using high quality exposed concrete structure; new developments in Russia, China, Singapore, the Philippines and Vietnam; the Slussen masterplan in the heart of Stockholm, Sweden and mixed-use residential schemes in Lebanon and Kuala Lumpur.

Elevation - West 0

20m

Project Details Appointment: 2012 Completion: 2021 Area: 18,450m² ElevationHeight: 88m - West 0 20m Client: RCC (Russian Copper Company) Collaborating Architect: P.M. VostokProekt Structural Engineer: Foster + Partners (Conceptual Design), VostokProekt, OOO Environmental Engineer: Foster + Partners (Concept), VostokProekt, OOO Landscape Architect: Hyland Edgar Driver Lighting Engineer: Jason Bruges Studio intelligent glass solutions | summer 2021

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It is clear that the meeting of minds, expertise and knowledge is fundamental, to not only the delivery of projects, but the much-needed development of technology, sustainable solutions and engineering marvels that define the trajectory of modern architecture. Indeed, collaboration is not limited to the ‘interhuman’ but also the materials we choose to explore and deploy, and technology that has ushered a new age of AI, data and digitally driven processes. From simplifying the construction of complex forms using robots to the coordination between specialist façade contractors and material specialists, we have highlighted the foundations on which, not only the glass industry, but our species has evolved – an innate ability to work together toward a common goal. This ability has led to the design and development of ever-more complex facades, exemplified by the projects penned on the pages of IGS Magazine. The technically challenging façade of the RCC Headquarters, designed by Foster + Partners and the German-American cooperation to build one of the most energy-efficient laboratories in the world are choice examples of what can be achieved through teamwork. In the second chapter of this edition, you will be introduced to more exemplary minds and projects, including the Battersea Power Station redevelopment, one of the largest regeneration projects in Europe. Discover how The European Space Agency and architects SOM developed a lunar habitat and the technical aspects of glass window design in space. Last, but by no means least, Dr. Hossein Rezai has ‘The Glass Word’ in an exclusive interview where we delve into his thoughts on collaboration, leveraging digital technologies and glass as a building material, both now, and in time still to come.

Global case studies and trends gaining traction: Walter P Moore

“The building façade is an untapped component for the reduction of carbon emissions”

Page 82

Water-Filled Glass

A new opportunity in glass construction in the fight against climate change

Page 101

PLENTY MORE TO COME

In the first half of our Summer Edition, the authors delved into the complex nature of collaboration when designing, engineering and building some of the world’s most innovative structures. Opened by renowned architect James Carpenter, you have been privy to the collaborative efforts and experimental spirit of the modernist vanguards in glass, architectural design and façade engineering.

The Glass Word with Dr. Hossein Rezai

“Value of collaboration has been undeniable in the ascent of our species to where we are…as the undisputed leading species on top of the food chain.”

Page 134

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Image credit: Bank of America Tower in New York City. Photo by Alizada Studios / Shutterstock.com

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Bespoke Façade Solutions for 21st Century Architecture

Courtesy of PLP Architecture

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he façade is an essential element of any building. It determines the building aesthetics and, even more important, its performance: thermal, acoustic and of course safety as it creates a protective screen between the inside of the building and the outside world. Over the years, buildings have become taller and more complex – an ever evolving process – and that has brought about increasingly complex technological challenges for all parties involved in the creation of such modern megastructures. This evolutionary spiral has affected the sector of curtain wall as well; there has been a shift from units composed of one sheet of glass mounted on an aluminum frame to more complex double and triple “skin” facades using increasingly advanced technologies which now characterise most newly built skyscrapers. The Permasteelisa Group, with its three Brands (Permasteelisa, Gartner and Scheldebouw), has been a key participant in this evolution, providing bespoke and advanced technical solutions, delivered to highest quality and standards. The Group’s project portfolio includes some of the landmarks of the cities that host them, all over the world. This is true for the Sydney Opera House, the Guggenheim Museum in Bilbao, the Walt Disney Concert Hall in Los Angeles, the Jin Mao and the World Financial Center in Shanghai, The Shard in London and the Laktha Center in St. Petersburg, as well as the Porta Nuova Garibaldi in Milan and many more, where the Group has worked together with the most visionary architects in the world. These three brands work in a coordinated way within the Group’s philosophy as a transnational global enterprise, capable of moving resources and organizations quickly and flexibly wherever the market developments may require, using a mix of local, regional and overseas resources, tools and knowledge to best fit the needs of any job developed within and by the Group. But there is a special place in the world where the three brands are always active at the same time. We are talking about London, where in the period 2020-2023 the Permasteelisa Group will complete around 20 projects. Among them, we’d like to briefly introduce three projects, each done by one of the brands: Battersea Power Station - Phase 3A, Prospect Place (Permasteelisa), 22 Bishopsgate (Gartner) and ONE Bishopsgate Plaza (Scheldebouw).

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BATTERSEA POWER STATION - PHASE 3A, PROSPECT PLACE intelligent glass solutions | summer 2021

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The Battersea Power Station redevelopment, one of the largest regeneration projects in Europe, aims to bring back to life both the iconic Power Station and the surrounding area on the south bank of the River Thames. By virtue of the holistic vision of the entire development team, the 42-acre site will be ‘re-electrified’ in a vibrant new destination for London, housing unique homes designed by internationally renowned architects, along with offices, shops, restaurants, green space and space for the arts with over 19 acres of public space. The overall project is divided into eight phases developed starting from the western side of the site and moving to the east. Phase 3 is the main gateway to the development, connecting the Northern line extension station with The Power Station. It features the construction of over 1,300 luxury apartments framing the Electric Boulevard running through the middle of the residential area, along with 50 new shops, cafes and restaurants, a tube station, a community hub and children’s playground. As a part of Phase 3A, Gehry Partners has designed Prospect Place, its first permanent residential development in the UK, as a series of buildings located on the opposite side of Electric Boulevard with a sculpted undulating façade. Permasteelisa is working on the envelope of the two Frank Gehry buildings of Phase 3A - adjacent to the iconic Battersea Power Station - delivering the design, manufacture and installation of around 27,200 sqm of the complex 3D shaped unitised envelope. The design of Prospect Place was inspired by the flowing sails of ships and by John Nash’s typical London Regency style façades. In architecture of such distinctive character, the surface area of the façade is never the same, capturing and reflecting light to provide an image of itself that is always new to the beholder. The façade’s sinuousness and dynamism are particularly striking. They are the result of the way the various components of the façade are put together to evoke the flowing sails of ships and trigger an interplay of particularly engaging reflections. Each building has its own style and the undulating façade of the buildings means

no two homes are the same. Sustainability is also paramount to the development of the project. The sustainability framework includes the benefits to the community, economy and environment along with the architect’s commitment to design excellence and dedication to making public and private spaces that feel good for the inhabitants and respect the surrounding context. The façade is designed to take full advantage of the brightness of the buildings, thanks to the special undulating shape created by the protruding and receding volumes of winter gardens and terraces. The choice to use white aluminium panels for the façade allows filling the common areas between the buildings with a warm and enveloping light coming from the sun’s rays reflecting on the façade. The envelope comprises three main elements: customised, unitised glass façade units creating the internal walls of the cladding, unique white surfaces that give the shape to the building and unique spandrel panels. Everything pivots around the key area near the spandrel panel and the transition between this and the vision glass. The innovative design has required the engineering and production of around 4,000 unitized panels, with aluminium profiles equipped with double-glazed or opaque infills, all different from each other and openable both with a folding or sliding panel. The undulating shape of the façade required about 3,300 aluminium closed infill white “boxes”, characterised by a unique and non-repetitive, customised shape. These boxes create the undulating and sinuous shape desired by the Architect. The project aims to achieve a BREEAM ‘Excellent’ rating under the BREEAM sustainability assessment method, so the visible panels are equipped with high thermal and solar performance low-E coated, extra-clear glass to maximise the light coming in, while preserving energy. The installation of the last panel is planned for the coming months and when completed Prospect Place will be a new architectural landmark for London.

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22 BISHOPSGATE 76

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At a height of 278 m (912 ft), 22 Bishopsgate is the tallest skyscraper in the City of London and the tallest skyscraper worldwide that features the particularly sustainable Closed Cavity Façade (CCF), the proprietary technology developed by Permasteelisa Group. Gartner, the German brand of the Group, cladded the office tower with 67,000 sqm (721,200 sq ft) of CCF façade with story-high units that are limited to a maximum depth not exceeding 250 mm (~9 7/8”). The closed cavity of the highly transparent glass units accommodates motorized dual color Venetian blinds providing sun and glare protection. The closed cavity façade offers huge improvements in daylight transmission and thermal performance, and together with the user-controlled smart blinds, it is a significant factor in the BREEAM ‘Excellent’ rating to which 22 Bishopsgate is designed. The story-high façade units feature a structurally glazed low-e coated glass units on the inside and Laminated Safety Glass (LSG) panes with selective coating on the outside which are glued directly to the thermally broken framework without carrier frame. These façade units with low-iron glazing allow up to 60% more daylight into the interior space than standard window glazing.

The 23-sided, faceted glass body of the tower is shaped to respect the town-scape views and makes a strong and calm backdrop to the surrounding towers and the neighboring historic buildings of the Bank of England. PLP Architecture worked with engineers from Formula 1 to model the building and the impact it would have on wind flows. The engineers created large-scale canopies, made out of steel and glass and ultrahighperformance reinforced concrete to tamp down the wind flow – testing 23 different designs before settling on the best one. The facetted façade geometry chosen by the architects also maximises views across the City and opens up a wide range of visual axes for future tenants. The entrance hall is a multi-level foyer conceived as an art gallery with curated temporary art exhibits. Permanent installations adorn the building, such as the British artist Alexander Beleschenko’s glass canopies. In addition to the 115 LSG panes for the canopies along Bishopsgate and above the main entrance, Beleschenko has further adorned approx. 50 insulating glass panes of the lobby façade as well as several wind mitigation screens. All glass panes have received ceramic digital print according to his file templates.

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ONE Bishopsgate Plaza is a mixed-use development located in the City of London designed by PLP Architecture for the UOL Group. The 43-story tower features a sophisticated form which steps as it rises. The scheme accommodates high-end retail components, restaurants and cafés on the ground floors, a luxury 5-star hotel providing wellness, meeting and events spaces along with a double-height ballroom and conference facility and, on the upper levels of the main tower building, 160 private residential apartments. Furthermore, the scheme includes a new public space filled with shops and cafes at its edges.

Courtesy of PLP Architecture

Scheldebouw, the Dutch brand of Permasteelisa Group, designed, engineered, manufactured and installed the façade of the main tower and the pavilion, a total of 20,000 sqm (215,300 sq ft) of unitized curtain wall and 11,000 sqm (118,400 sq ft) of brise soleil. The glass pavilion features structural glass fins for both the façade and the roof. These are designed in a way to form a structure of 3-hinge frames on which double glass units can be toggle fixed and structurally sealed. The pavilion is a full glass box with a roof pitched in two directions. In order to keep the internal atmosphere comfortable, the glass features a high-performance coating. The roof glazing and the West and South façade glass have a custom frit pattern to lower the heatgain even further. Within the North and South elevation, a portal frame with automated double doors gives access to the pavilion. Inside, an escalator and a lift bring visitors down into the ballroom area. Scheldebouw worked with PLP Architecture to develop a special LED lighting system incorporated into the stainless steel connection profiles between the glass frames and the façade and roof glazing units. The development of bespoke design and engineering solutions overcame the many challenges posed by the construction of this amazing fully transparent pavilion.

ONE BISHOPSGATE PLAZA

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Courtesy of PLP Architecture

Massimiliano Fanzaga is the Communication Manager of the Permasteelisa Group. Supported by a team of specialists spread in all geographic regions where the Permasteelisa Group operates, he is constantly dealing with Media, Universities and important International Events ensuring the right positioning of the Permasteelisa Group brand in the relevant market. Massimiliano graduated in 2001 at the University of Milan with a degree in Political Science, course of studies in political economy. Driven by his love for architecture and the desire of being part of an international group, in 2008 he started as an Investor Relator in the Permasteelisa Group.

Courtesy of PLP Architecture

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TRANSPARENT ARCHITECTURAL STRUCTURES A century and a half after its founding by the self-made merchant Ernest Cognacq and his wife Marie-Louise Jaÿ, the second-oldest department store in Paris gets a facelift. The Pritzker Prize winning duo Sanaa designed this contemporary building renovation and wavy façade. Photograph by Pierre-Olivier Deschamps/Agence VU' / Courtesy of La Samaritaine

RENO

In the architecture industry and in the media, most of the attention focuses on new buildings, often designed to meet high environmental performance standards. At the same time, some of our greenest buildings may be hidden in plain sight: they’re the ones we already have. Today, we are witnessing a new awareness of the benefits of retrofitting buildings, rather than demolishing and replacing them with new builds. This is especially true in Europe and in several large cities in Asia. Increasingly, developers are seeing both the environmental and the economic advantages of remodeling buildings, while integrating new sustainable strategies.

“At its best, renovation engages the past in a conversation with the present over a mutual concern for the future” - William Murtagh 80

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Coming in September…

IGS Autumn 2021

OVATION NATION Adaptive reuse, the practice of renovating and adapting existing buildings to serve newand future needs, must become an essential part of any city’s strategy for sustainable urban development. Glass has its role to play in this story, indeed a protagonist, in adaptively retrofitting existing buildings to prepare them for the future. In the Autumn edition of IGS magazine, we explore glass facade renovations, retrofitting and adaptive reuse through project case studies, insightful thought leadership and interviews, unraveling the complex nature of the modern retrofit building envelope. From ground-breaking glass technologies to best practice in retrofitting building facades, the industry speaks!

This is IGS – Nothing more, nothing less…NOTHING ELSE intelligent glass solutions | summer 2021

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

Exploring Embod in Building Enclo

The building façade is an untapped component for the reduction of carbon emissions Bank of America Tower (formerly Capitol Tower) Shau Lin Hon – Slyworks Photography

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died Carbon osures

Katherine Chan, MSFE, Associate and Senior Enclosure Technical Designer, Walter P Moore Laura Karnath, AIA, NCARB, Senior Associate and Senior Enclosure Technical Designer, Walter P Moore

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he last year has shown us that as a global community we must mobilize together to achieve solutions in response to a crisis— we are interconnected, and wide-reaching solutions cannot be achieved in a vacuum. The A/E/C industry along with scientists, academia, and policy makers alike agree that climate change is indeed a crisis. In order to prevent catastrophic warming of 2 degrees or more, we must drastically reduce greenhouse gas emissions across every industry. It is common knowledge among building industry professionals that building operations account for approximately 40% of global emissions. Since the founding of Architecture 2030 in 2002, our industry has been highly successful at reducing building energy consumption and making buildings more operationally efficient. More important, we continue to make progress in the quest for net zero.

embodied carbon emissions occur up front, this means that reducing embodied carbon is even more crucial to achieving near-term emissions reductions goals. Increasing operational efficiency could have a payback period that stretches across the coming decades, whereas embodied carbon reduction strategies are preventing emissions now, while materials are being sourced and buildings are being constructed. While emissions reduction has to date primarily been the realm of architects and MEP engineers, now every sector of the building construction industry has a role to play in the effort to reduce embodied carbon.

For most buildings, the foundation and superstructure are responsible for the majority of the building’s embodied carbon, followed by the enclosure system. Currently, there is not yet robust embodied carbon baseline data in the same way that there is for operational carbon, but the industry is working on it. The Until recently, it is the other piece of the building Carbon Leadership Forum at the University emissions pie that has received less attention. of Washington has published the Embodied That is the approximately 11% of global carbon Carbon Benchmark Study and continues emissions that come from the extraction, to collect more data and case studies on manufacture, and transport of building embodied carbon in buildings. In addition, SE materials, their maintenance and replacement 2050 is collecting embodied carbon data from throughout a building’s life, and their eventual engineering firms to develop embodied carbon disposal. This is known as embodied carbon. baseline data for structures. To encourage further collection of baseline data, LEED v4.1 A significant portion of a building’s embodied offers a credit for performing a Whole Building carbon emissions occur before and during its Life Cycle Assessment (WBLCA) to understand construction, while the operational emissions the environmental impacts of building FIVE TOTAL CHARTS/GRAPHS BELOW from a building’s energy use are drawn out over materials, including embodied carbon, and the course of the building’s lifespan. Because GRAPHIC 1: Global CO2 Emissions by Sectorprovides credits for reducing impacts from a

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Bank of America Tower (formerly Capitol Tower) G. Lyon Photography, Inc.

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

Bank of America Tower (formerly Capitol Tower) G. Lyon Photography, Inc.

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baseline design. WBLCA can help designers understand where the embodied carbon hotspots are in their design and where there are opportunities for reduction. While there are many ways to reduce the embodied carbon in a building project, the façade is an untapped component as it lies at the intersection of several strategies for reduction of building industry carbon emissions. Well-designed high-performance facades can lead to reduced energy use through thermal efficiency and by balancing shading with daylighting, depending on climate zone and time of year. However, many common façade materials are highly carbon intensive to produce. Being more intentional about where and how to use them can hold the key to optimization. A Closer Look at the Impacts of Façade Materials To illustrate the effects of façade design choices on embodied carbon, we have completed several design exercises to assess the embodied carbon of various wall assemblies per square foot of façade area. In an assessment of opaque wall assemblies prepared for Walter P Moore’s Stewardship Report Embodied Carbon: A Clearer View of Carbon Emissions, we found that insulation and cladding choices can make a big difference in the embodied carbon of a wall assembly. Our next step was to look at glazing assemblies. We used Tally, a life cycle assessment (LCA) tool for Revit, to assess three different options for a 20-foot-high atrium curtainwall. We wanted to understand how three different mullion strategies would impact the embodied carbon of the overall wall. The first strategy we looked at was to minimize the size of the aluminum mullion by using a secondary steel hollow structural section tube at mid-span. The second strategy was to use a steel reinforced mullion to achieve the span, and the third option was to use a deep aluminum mullion with no reinforcing that was also capable of achieving the desired span. Our goal was to find out how much of an impact do these structural and aesthetic choices have on embodied carbon. In this design exercise, we found that the deep mullion option had the lowest embodied carbon. However, a deep mullion is not 86

OPTION 1: 6” Mullion, no reinforcing HSS 6x6x3/8 supporng at mid span 3 transoms at 6” depth

OPTION 2: 8” Mullion with steel reinforcing 3 transoms at 6” depth

always favored by designers who want to minimize the depth of the system. The next best option, in this case, is to use secondary steel to break up the span and enable the use of a smaller mullion. The steel reinforced mullion had the highest impact of the three options we studied, with embodied carbon approximately 20% higher per square foot. Once multiplied across an entire façade, this can make a significant difference in a building’s overall embodied carbon. It could be the difference that enables the project to get a LEED point for environmental impact reduction. It is important to note that each project is unique, and these results are specific to the conditions studied in this design exercise. This highlights the importance of using LCA to assess the embodied carbon impact of the design decisions that result from each project's unique conditions.

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OPTION 3: 10” Mullion, unreinforced 3 transoms at 6” depth

Diving deeper into each assembly, we can identify carbon hotspots and understand how much embodied carbon each component of a glazing assembly is responsible for. Looking at the curtainwall only from the first strategy, we wanted to find out the embodied carbon contributions of the insulating glass units (IGU), aluminum, and steel, normalized per square foot of façade area. In this example, the glass is the biggest contributor to embodied carbon; however, the aluminum has carbon impact disproportionate to its share of the mass of the system. It represents 21% of the mass of the system but is responsible for 32% of the embodied carbon. As a result, reducing aluminum quantities may be a good place to start in order to reduce the overall embodied carbon of this system. This design exercise provides one example of how embodied carbon can be considered as a metric, balanced with aesthetic concern and cost.

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION GRAPHIC 3: Embodied carbon bar graph for three curtainwall options

Façade Performance and Embodied Carbon In addition to the study of the three design strategies discussed above there are many additional factors that go into façade design that have embodied carbon implications.

GWP by Wall Area (KgCO2eq/sf) 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00

Option 1

Option 2

Option 3

GWP Steel HSS

Steel reinforcing

Aluminum extrusion

Glass

IGU spacer

Low-e coating

Fluoropolymer coating

GRAPHIC 4: Mass vs Carbon pie charts

Sum of Global Warming Potential

1%3%

13%

46%

32%

Steel HSS

Aluminum extrusion

Fluoropolymer coating

Glass

IGU spacer

Low-e coating

IGU spacer

Low-e coating

Sum of Mass Total (kg)

0% 1% 23%

54% 21% 1%

Steel HSS

Aluminum extrusion

Fluoropolymer coating

Glass

To consider what adjustments can be made to optimize for embodied carbon, we can start by examining performance requirements and optimizing the materials that provide the required performance. For example, structural performance drives mullion design and glass buildup, and protection against air and water infiltration is directly affected by gaskets and sealant. For the latter items, there is limited environmental impact data available in commonly used LCA tools. Data on the environmental impacts of materials come from Environmental Product Declarations (EPDs), which can be described as a “nutrition label” for materials, providing information on environmental impacts in a standardized format. There are not currently EPDs available in the Tally tool for gaskets or sealant in curtain wall assemblies, so we do not have a complete understanding of their role in the overall embodied carbon of a curtainwall assembly at this time. First, we will explore what opportunities there are to optimize glazing and mullion design from an embodied carbon standpoint, with a focus on conventional extruded aluminum curtain walls. We can start by optimizing the quantity of aluminum used. One possibility for reducing the cross-sectional area of curtainwall members and thereby reducing embodied carbon, is to use channel sections with a thin trim for the head, intermediate transoms, and sill extrusions. This strategy can also simplify fabrication and installation. Another possibility to explore is using a capless structurally silicone glazed curtain wall system instead of a capped mullion system. A structurally silicone glazed system can result in a reduction in aluminum quantities, but an increase in silicone. Better data on the embodied carbon contribution of various types of sealant will enable a more complete understanding of the effectiveness of structural silicone glazing as an embodied carbon reduction strategy. In addition to structural performance, enclosure material choices and quantities are driven by a variety of other performance requirements such as fire rating, acoustics, and thermal

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City of Hope Benny Chan-Fotoworks

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GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

City of Hope Benny Chan-Fotoworks

performance. For example, in many cases, a standard IGU with ¼-inch-thick panes of glass will meet structural performance requirements. However, fire performance may require thicker glass panes. Acoustic performance could require additional layers of glass or a wider airspace. The knock-on effect of increasing the thickness and weight of the IGU is an increase in mullion size to support the additional material. While key performance requirements cannot be relaxed, there are still opportunities to optimize material use. For facades with special performance requirements, introducing additional materials only in the areas where they are needed is key to keeping both cost and embodied carbon low. Often, the glass buildup or mullion size needed in the most extreme case is applied across the entire building for aesthetic consistency. In a recent project that our team worked on, a different approach was taken. Acoustically enhanced glazing was used only on the side of a building facing a busy road, and all other facades used a more standard buildup. The Future of Low-Carbon Façade Design So, what does the future hold for low-carbon façade design? As jurisdictions take a critical eye to their building codes for energy efficiency and operational carbon emissions, embodied

carbon will be the next frontier. This will make lowering the embodied carbon crucial to the design and construction process. In addition to increasing the use of WBLCA in design, we also anticipate these limits to provide a renewed interest in adaptive reuse and retrofits of existing buildings. The impetus behind this is twofold. First, the existing building stock will need retrofits to meet updated energy codes. Secondly, because a building’s primary structure is typically the source of most of its embodied carbon, adaptive reuse of existing buildings becomes a crucial strategy for embodied carbon reduction. The primary structure can be preserved, while enclosure and interior components are replaced. Reuse of an existing structure is typically a lower-carbon alternative to new construction. The commercial viability of the retrofit market is staggering. In a recent study referenced in their strategy piece Bring the Retrofit Market to Scale by the Urban Green Council in New York City, almost 85% of the city’s existing buildings are likely to still stand in 2050. This study served as major impetus to drive down their energy use as an essential step to addressing climate change, culminating in Local Law 97. The Urban Green Council’s market analysis forecasts that Local Law 97 could lead directly to a new $20 billion retrofit market. For example, the New York City Housing Authority’s Capital Plan for

intelligent glass solutions | summer 2021

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

City of Hope Benny Chan-Fotoworks

thyssenkrupp’s Innovation and Qualification Center Walter P Moore

intelligent glass solutions | summer 2021

thyssenkrupp’s Innovation and Qualification Center Walter P Moore

New York City Housing Authority

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

FY 2019 – 2023 Capital Plan by Work Type New York City Housing Authority (In Thousands) FY 2019 – 2023 Capital Plan by Work Type (In Thousands) FY 2019 – 2023 Capital Plan by Work Type (In Thousands)

New York City Housing Authority

Katherine Chan Associate Senior Enclosure Technical Designer Kat has a background in enclosure design and engineering with a structural and building physics emphasis. As a Senior Enclosure Technical Designer, she excels at aligning design intent with specific project performance requirements, juggling sustainable enclosure design with an appreciation for leveraging the façade systems that are currently available in market. Kat recently participated in the multidisciplinary ENCASE team for the Department of Energy hosted competition to leverage robotics and building retrofits called E-Robot.

Total: $6.384 Billion Total: $6.384 Billion 

Other includes Fire Safety, Garbage Disposal, Energy projects and A & E/CM Fees. Total: $6.384 Billion

Source: New York City Housing Authority Capital Plan 2019-2023



Other includes Fire Safety, Garbage Disposal, Energy projects and A & E/CM Fees.

 Other includes Fire Safety, Garbage Disposal, Energy projects and A & E/CM Fees. 2019-2023 includes a total of $6.384 billion in disassembly or reuse of glazing is commercially funding from the federal, state, and city levels. viable—and project jurisdictions have codified Of the anticipated work and subsequent limits on embodied carbon—we could see spending to maintain and retrofit existing these processes propelled into common use and housing, $158 million is targeted at building thus improve the embodied carbon of glazing. exteriors. As façade consultants, we work to make smarter As2019 we build new buildings and reclad existing design decisions and material choices, and Five Year Capital Plan Pagewe 27 buildings, the lifespan of a façade system is encourage our clients to consider embodied an2019 important consideration. carbon as a performance and design metric, Five Year Capital Plan The lifespan of Page 27 the entire system is often driven by the first much like structural, thermal, acoustical, components toCapital fail. AsPlan the façade ages, gaskets fire, and water infiltration protection. WePage 27 2019 Five Year and sealants deform, allowing air and water to believe that whole lifecycle carbon must be infiltrate to the interior, and the cavity within considered on every project so that the impacts the IGU will leak, causing air exchange and loss of upfront design choices over time can be of thermal performance. The next progression better understood, enabling the balancing of in advanced façades could be designing for embodied and operational carbon. disassembly and salvaging façade cladding materials and components. Glazing panels in We challenge manufacturers and contractors an IGU could be disassembled and reused, to find innovative ways to reduce the emissions assuming that the low-e coating is still effective; associated with materials manufacturing, however, there are not currently facilities or transport, installation, and reuse or salvaging. commercial markets to take advantage of Together we can make great strides to counter these opportunities. We believe this to be an global warming. It starts with taking a critical eye untapped part of the market that can leverage on how we design, build, reuse, recycle, existing technology. Once designing for and adapt.

Laura Karnath Senior Associate Senior Enclosure Technical Designer Laura has a background in building information modeling and data-driven design and is working to apply these principles to sustainable enclosure design. As a senior enclosure technical designer, she consults on projects with complex facades to assist architects in achieving their design, performance, and sustainability goals. Laura recently cofounded the Los Angeles hub of the Carbon Leadership Forum, an organization that connects professionals across the building industry to share research, best practices, and innovative approaches to decarbonize the built environment with a focus on embodied carbon.

intelligent glass solutions | summer 2021

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Building High Performing Teams to Deliver Complex Façades Neil Dobbs, Head of Façades at Multiplex

D 22 Bishopsgate on the London Skyline

Image courtesy of Multiplex GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

intelligent glass solutions | summer 2021

Katherine Chan, MSFE, Associate and Senior Enclosure Technical Designer, Walter P Moore Laura Karnath, AIA, NCARB, Senior Associate and Senior Enclosure Technical Designer, Walter P Moore

Bank of America Tower (formerly Capitol Tower) Shau Lin Hon – Slyworks Photography

intelligent glass solutions | summer 2021

Exploring Embodied Carbon in Building Enclosures

The building façade is an untapped component for the reduction of carbon emissions

All photos by Brad Feinknopf

intelligent glass solutions | summer 2021

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

intelligent glass solutions | summer 2021

Introduction

The unfortunate ammonium nitrate explosion from August 2020 in Beirut, Lebanon the importance of curtain wall façades’ resistance to extreme loadings. A mid-rise approximately 1km from the explosion was severely damaged (Figure 1).

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

Introduction The unfortunate ammonium nitrate explosion from August 2020 in Beirut, Lebanon, reminds us all of the importance of curtain wall façades’ resistance to extreme loadings. A mid-rise building situated approximately 1km from the explosion was severely damaged (Figure 1). The façade system of this 7 story high building, about 10 years old, integrated a combination of skylights, unitized and stick frame systems using various DOWSIL™ bonding silicones. The façade glass panels were limited in size (about 2.5m width and 0.8m height) and bonded on 4 sides using a 12mm by 6mm joint of DOWSIL™ 993 Structural Glazing Sealant. The glass panes were insulating glass units (IGU) of 8mm toughened and a 55.1mm laminated glass on the inside sealed using DOWSIL™ 3362 Insulating Glass Sealant. On-site inspection after the event showed that no silicone joints were compromised cohesively. The broken glass was still retained around its perimeter by the silicone. The hardness of the material was still within expected range (Figure 2). A number of design parameters (the use of toughened glass and a limited lamination thickness for the IGU, leading to quick breakage of the glass, small pane dimensions and pane aspect ratio), were probably favorable and limited the loading on the structural joint, but still the performance of this relatively small joint, not designed to resist such types of loading, might surprise. Figure 3 shows a silicone bonded glassfin which was under installation on a new build project as the Beirut explosion occurred. The glass was broken yet the images illustrate how the PVB still retains the broken glass. The wavy shape of the fin demonstrates the extreme plastic

Figure 1: broken glass panes on the building after the Beirut explosion in August 2020

deformation and the membrane rupture. When the structural Figure 1: broken glass panes onbehaviour the building aftermembrane the Beirut post explosion in August 2020 of the PVB. The silicone bonding at top and joint connection is properly designed to bottom kept the deformed glassfin in place. accountabout for parameters suchold, as glass thickness a combin The façade system of this 7 story high building, 10 years integrated The U-shape and favorable load orientation or laminate type, structurally glazed units unitized and stick frame systems using various DOWSIL™ Structural Glazing Silicones (occurring perpendicular to the plane of the contribute to limit damage during a blast panels werethan limited in helped size (about 0.8msilicone height) and structurally glaze glassfin rather in plane) reducing2.5m width event. Aand structural connection has been the amplitude of the loading experienced by shown to reduce ejection of glass panes and a 12mm by 6mm joint of DOWSIL™ 993 Structural Glazing Sealant. The glass panes we the joint. Once more, this joint demonstrated an maintain their attachment to the frame after units (IGU) of 8mm toughened and a 55.1mm laminated glass on the inside sealed usi excellent performance. glass breakage even in extreme blast loading Insulating Glass Sealant. On-site inspection cases. after the event showed that no sil Although both cases were not specifically compromised cohesively. The broken glass was still retained around its perimeter b designed to be blast resistant and some happens during a blast event? hardness of the material was still within What expected range (Figure 2). parameters were favorable to the joint Historically, the first blast resistant façades resistance, the performance of silicone bonded would use channel laminated glazed systems façades (combined with laminated glass) in with 30-40mm of glass edge covered by sealant blast events can ensure improved performance gunned in between the metal channel and the compared to other design options, thanks to glass. This detailing was, however, perceived the increased retention capacity of the glass as expensive and inaesthetic. In 1997, one of

General Business

Figure 2: on site hardness and deglazing test after the blast event

gure 2:Figure on site and deglazing test aftertest theafter blastthe event 2:hardness on site hardness and deglazing blast event 94

intelligent glass solutions | summer 2021

however, perceived as expensive and ina glazed element of 3m x 3mGAINING was TRACTION performed GLOBAL TECHNOLOGIES AND TRENDS in 4 panels which were bonded on the 4 s only 26mm x 6.4mm. The glass panes were of PVB. The charge comprised of a modera 800mm above ground level which resulted close to 500m/s. After testing, it was foun with the frame system. When breaking, th deformation can be such that the plate esc retained the glass in position and did not s joints were much smaller compared to the opened the path to the use of structurally

specifically dimensioned for blast resistance.

Figure 3: front and internal view of the glazed façade after the blast event in Beirut: glass fin is plastically deformed but still retained at top and bottom by the structurally glazed joints

the first field tests of a structurally glazed element Figure 4: open field explosion test of 3m x 3m was performed (Figureand 4, Hautekeer Figure 3 front internal view of the glazed façade after the blast event 2001). The total glazed area but was divided in 4 deformed still retained at top and bottom by the structurally glazed joints panels which were bonded on the 4 sides using a DOWSIL™ 993 Structural Glazing Sealant joint of only 26mm x 6.4mm. The glass panes were insulating glass units, with 12mm glass laminated with 5 plies of PVB. The charge comprised of a moderate 12kg TNT weight placed quite close at 6.5m from the glass, 800mm above ground level which resulted in the pressure wave hitting General Business the glass after 6msec at a speed close to 500m/s. After testing, it was found that the laminated glass was cracked and deformed in line with the frame system. When breaking, the laminated glass tends to lose its flexural rigidity and pane deformation can be such that the plate escapes from its mechanical fixations. The silicone joint however retained the glass in position and did not show any sign of damage or adhesion loss. The tested silicone joints were much smaller compared to the conventional channel designs used up until this point and this opened the path to the use of structurally glazed details that can withstand bomb blast pressure.

in Beirut: glass fin is plastically

Figure 3 front and internal view of the glazed façade after the blast event in Beirut: glass fin deformed but still retained at top and bottom by the structurally glazed joints

General Business

Field testing is expensive and time consuming due to the high number of tests needed to understand the influence of the different parameters. Therefore, it is important to understand the blast event as well as the silicone performance to be able to accurately model and predict behavior through advanced calculations and simulations. glass solutions test | summer 2021 Figure 4: openintelligent field explosion

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

A complex loading system The silicone sealant, essential for retaining technique. Using these experimental blast The first few milliseconds of a blast event consist the glazing, is first compressed by the glass testing data, typical deflection angles of 4° of a positive pressure hitting the building bearing against the frame or mullions, to 40° and typical line loads in the range of (Figure 5, Dewey 2010). The positive phase is and then subjected to a complex triaxial 60- 160 N/mm were estimated for a laminated determined by its impulse, which is the total state of superimposed bending, shear, and glass of 1.0 x 0.8 m² size. Using a range of 5 to load exerted by the explosion whereby not only tensile stresses as the glazing is crazed and 20 milliseconds for the positive pressure phase the overpressure, but the distance from the deformed. Once the pressure wave cracks and the typical displacement ratios given above explosion also plays a role. The pressure of the the glass plies of the laminated glass system, (h/b ratios of 0.03 to 0.2), maximum center explosion quickly decreases (as a function of the the laminate behaves as a membrane with pane velocities for successful blast tests, i.e., cube of the distance). During this phase, the glass the interlayer ensuring the integrity through without the pane dislodging, are estimated to deflects towards the interior of the building. This plastic deformation. The pane’s flexibility and fall in the 4 to 30 m/s range. Considering the is considered to be the most critical phase as deflection increase greatly, which will, to the post-breakage ductility of the laminated glass glass should not break and enter the building contrary of windloading, mainly load the joint at high strain rates, an estimate for maximum and, therefore, the positive phase is typically in shear. Besides shear, additional forces impact movement rates of the sealant ranged thethe main silicone concern in performance the design phase. to As the the silicone joint, such as in and out of plane between 1through and 15 m/s.advanced Similarly (Mueller be able to accurately model and predict behavior load gets reflected by the building and the forces and moments, leading altogether to a 2006) calculates a maximum glass elongation calculations and simulations. surrounding construction, its impulse becomes complex loading behavior. The deformation of of 160mm after 17ms for an element span of negative. The glass itself will at first continue to the silicone after the glass breakage is therefore b=800mm. Converting this to glass rotation deflect inwards, due to inertia, then it will start the most demanding part of the loading and α, an approximate maximum load speed of deflecting outwards following the negative the focus of design. the sealant at the glass edge of 0.5 to 0.8m/s A complex loading system phase with some delay. This phase shift between is obtained, assuming a 20mm sealant bite. plate bending and suction force reduces the The speed of deformation or strain rate of The the strainbuilding ratio of the(sealant The first few milliseconds of a blast event consist of a positive pressure hitting Figureitself 5, is, therefore, glass pane deflection, as the external force is the silicone is another important element lower than the speed of the glass Dewey 2010). The positive phase is determined by its impulse, which is the total load exerted by theduring now opposite to the displacement. The glass influencing the silicone’s response. The realistic the explosion and typically depends on the explosion whereby not only the overpressure, but the distance from the explosion also plays a role. The bending towards the outside of the building load speed for the structural edge sealant geometric behavior of the system. However, pressure the quickly (aselement a function theblast cube of the distance). During this phase, is now in phaseof with theexplosion suction force, leadingdecreases of a façade underof bomb can it is significantly higher than the strain rate the glass deflectsattowards interiorbeofobtained the building. This is considered to beobserved the most criticalorphase to enlarged deformation the secondthe flexion by analysis of test results. For for normal extremeas wind events peak. This mechanism explains why in most instance, (Kranzer 2005) reports pressure and such as typhoons and hurricanes glass should not break and enter the building and, therefore, the positive phase is typically the mainwhich makes bomb blast testing, thedesign glass detached displacement versus time measured silicone material characterization at concern in the phase.from As the load gets reflected by histories the building and thespecific surrounding construction, the frame is found in front of the façade as glass on laminated glass panes (two panes of 3 high speed necessary. its impulse becomes negative. The glass itself will at first continue to deflect inwards, due to inertia, then pane deformation and stress in the joint are the mm thick float glass laminated with 1.52 mm it will start outwards following thefilm) negative with somebydelay.Silicone This phase shift between largest during the deflecting second deflection peak. The thick PVB exposedphase to blasts generated behaviour at high strain rate platephase bending suction force reduces glassfield pane deflection, as the force is now process opposite negative shouldand not be underestimated, highthe explosive charges or pressurized air external Since the deformation occurs within a as itto hasthe a long duration and will also impact releases in shock tubes. The glass area loaded few milliseconds, giving rise to stresses in the displacement. The glass bending towards the outside of the building is now in phase with the a structure which has been fragilized by the by the blasts was 1.0 x 0.8 m² and the blast silicone sealant close to its performance limits, suction force, leading to enlarged deformation at the second flexion peak. This mechanism explains why positive wave. Because there is little energy impulses were designed to take the laminated it is of importance when selecting products in in most bomb blast testing, the glass detached from the frame is found in front the of the façade as glass pane loss associated to glass deformation, most of glass to the point when the glass pane just design of blast-mitigating glazing systems and stress the joint arecrazes the largest deflectiontopeak. The negative phase thedeformation energy associated to the glassin deformation (referred during to as the the Breaksecond Safely / No understand the response of silicone sealants is recovered and the interaction between the Hazard level). Under these conditions, center to high strain rates and high stress loads. should not be underestimated, as it has a long duration and will also impact a structure which has been inward and outward movement leads eventually pane displacements of around 15 mm and fragilized by the positive wave. Because there is little energy loss associated to glass deformation, most to complex higher modes of deformation and center pane velocities of 4.9 to As a hyperelastic material, the typical strength of the energy associated to the glass maximum deformation is recovered and the interaction between the inward an oscillation of the glass pane similar to a spring 7.5 m/s were measured using a non-contact, and elongation of a silicone sealant depend on and outward movement leads eventually to complex higher modes of deformation andThe anperformance oscillationofof system. laser-optical displacement measurement load speed. conventional the glass pane similar to a spring system. structural silicone materials under normal (wind) loading is typically evaluated at quasiFigure 5: Schematized pressure evolution static strain rates of 5mm/min (~8E-5 m/s) as with time characteristic of a blast wave specified in ETAG002 (EOTA 2012) and ASTM (Friedlander waveform)(Dewey 2010) C1135-19 (ASTM 2019). As seen above, typical designs indicate that speeds of 2.5 m/s in tensile and 1.1 m/s in shear should be applicable for most of the bomb blast resistant structural glazing facades. However, it is recommended that a check be made for the relevance of these values for each specific case by the designer of the façade. Otherwise, further investigation could be necessary.

Figure 5: Schematized pressure evolution with time characteristic of a blast wave (Friedlander waveform)(Dewey 2010) intelligent glass solutions | summer 2021

The silicone sealant, essential for retaining the glazing, is first compressed by the glass bearing against the

physical properties. The flexibility of the silicone under these conditions will allow the displacements between glass and frame without breaking cohesively. In addition, the product will be dimensioned based on an increased breaking strength. The values observed for DOWSIL™ 993 Structural Glazing Sealant are reported in Table 1.GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION Table 1: ultimate strength and elongation in tension and shear for DOWSIL™ 993 Structural Glazing Sealant at increasing testing speed

Another parameter of importance in blast is the tear resistance. This test evaluates the tensile strength on H bar joints of 12mmx12mmx50mm with a preliminary applied incision of 5mm. The test is normally performed at the standard speed of 5mm/min (EOTA 2012). At this velocity, peak tear strength is around 127N ± 13N for DOWSIL™ 993 Structural Glazing Sealant. When performing this test at a tear velocity of 1m/s,

5mm/min

1.0 m/s

2.5m/s

5.0 m/s

1.37

2.37

2.82

2.97

160

200

194

0.64

1.77

2.13

2.24

109

206

224

229

350

Table 1: ultimate strength and elongation in tension and shear for Another of Glazing importance is thetesting tear resistance. This test evaluates the tensile strength on DOWSIL™parameter 993 Structural Sealantinatblast increasing speed 300 300

150 100

Run2

Tear Force [N]

Run3

200

Tear Force [N]

H bar joints of 12mmx12mmx50mm with a preliminary applied incision of 5mm. The test is normally Run1 250 250 peak tear strength is around performed at the standard speed of 5mm/min (EOTA 2012). At this velocity, Run3 200for DOWSIL™ 993 Structural Glazing Sealant. When 127N ± 350 13N performing 200 this test at a tear velocity of 350 1m/s, the tensile tear strength increases Run2 to 306± 2N. A similar increase in tear elongation can Run1be noted. 150 300 300 With ~2.4X increase in tear force and ~2.1X increase in tear elongation,150 the total tear energy at 1m/s is ~ Run1 Run2 250 250 100 5X of the tear energy at 5mm/min (Figure 6). 100 200

5 10 15 100 -50 0 50 50 Tensile Elongation at 5mm/min [mm]

Run1 Run2 Run3

Run3

150

-50 0

0 0 General Business 5 10 15 -50 0 -50 0 Tensile Elongation at 5mm/min [mm]

Tear Elongation at 1m/s [mm]

Figure 6: Comparison of tensile tear resistance of DOWSIL™ 993 Structural Glazing Sealant at 5mm/min and at 1m/s

The same increase of tear performance is observed for shear modeat(Figure Figure 6: Comparison of tensile resistance of DOWSIL™ 993 Structural Glazing Sealant 5mm/min 7). and at 1m/s The same increase of performance is observed for shear mode (Figure 7).

400

350

300

Shear 5mm/min

300

Shear Tear Force

The silicone sealants studied all toughened and appeared to stiffen with increasing movement rates. The toughening of the sealant results from a simultaneous increase in maximum strength and strain, which translates into substantially increased fracture energy, which corresponds to the area under the stress-strain curve. For a well-balanced, blast mitigating window design, the increased toughness results in greater blast capacity, assuming the silicone sealant represents the weakest link in the performance chain of the design. In tension, both tensile strengths and corresponding strains increase by a factor of about 2 to 2.5 for all three sealants with an increase in movement rate from 50 mm/min to 5.0 m/s. In the shear experiment, a corresponding increase in shear strength by a factor of 3.5 and strain by a factor of 2.1 is observed. These increased tensile strength and elongation indicate a strain dependent relationship of physical properties. The flexibility of the silicone under these conditions will allow the displacements between glass and frame without breaking cohesively. In addition, the product will be dimensioned based on an increased breaking strength. The values observed for DOWSIL™ 993 Structural Glazing Sealant are reported in Table 1.

DOWSIL™ 993 Structural Glazing Sealant H-bar tension Strength smax (12x12) mm² [MPa] Elongation e [%] at Fmax H-bar shear Strength tmax (12x12) mm² [MPa] Elongation g [%] at Fmax

Shear Tear Force

Extensive blast testing at high speed (Yarosh 2010) was carried out on silicones used for structural bonding. The aim of the tests was to investigate the material properties at the increased load velocities occurring in shock waves. High speed tests were conducted at displacement rates of 1.1m/s and 2.5m/s and shear tests at 1.1m/s. These speeds consider the relative displacement between the glass and the frame, in both directions. This means a load application velocity 240 to 300 times higher than the maximum standardized tensile and shear test speeds and 30 000 higher than the standard tensile speed (5 mm/min). A variety of specimen sizes were evaluated. The length of the H-bar joints was 18mm and the depth and thickness were in the range of 6-16mm. The tests were conducted on single sided joints.

Shear 5mm/min

250

Shear 1m/s

200 200

Shear 1m/s

150 150 100

100

10Shear Distance 15 [mm] 20

Shear [mm]Sealant at 5mm/min and at 1m/s Figure 7: Comparison of shear tear resistance of DOWSIL™ 993Distance Structural Glazing

These be explained through the unique of the silicone sealant. The Figure observations 7: Comparisoncan of shear tear resistance of DOWSIL™ 993 composition Structural Glazing Sealant at 5mm/min and at 1m/s viscoelastic nature of amorphous rubbers (such as silicones above glass transition and crystallization temperatures), derives from of the through polymer chain the atomic scale (rotations between These observations canthebemobility explained the on unique composition of the silicone sealant molecular units)nature and on the macroscopic scale (straightening of the chain between The strainand crystalliz viscoelastic of amorphous rubbers (such as silicones abovecross-links). glass transition rate sensitivity reflects the timescale required polymer chain re-orientations to take place. At the tensile tear strength increases 306± 2N.for A these These observations be explained through temperatures), derives from to the mobility of the polymer chain can on the atomic scale (rotations bet low strain rates the polymer chains have sufficient time to re-orient themselves and the storage modulus similar increase in tear elongation can be noted. the unique composition of the silicone sealant. molecular units) and on the macroscopic scale (straightening of the chain between cross-links). The of the rubber is low. At high strain rates, the deformation of the polymer chains is restricted to bending With ~2.4X increase inchemical tear force and ~2.1the X required The nature of amorphous rubbers rate sensitivity reflects the timescale forviscoelastic these re-orientations and stretching of the bonds, and storage modulus of thepolymer rubber canchain increase by up to three to take pla increase inmagnitude. tear elongation, the total tear energy (suchtime as above glass and orders of As apolymer silicone bond is loaded, cracks willsilicones eventually start to formtransition and propagate. low strain rates the chains have micro sufficient to re-orient themselves and the storage mo Figure 7: Comparison of shear tear resistance of DOWSIL™ 993 Structural Glazing Sealant at 5mm/min and at 1m/s

at of 1m/s ~ 5X of the tear At energy 5mm/min crystallization temperatures), derives from the theis rubber is low. highatstrain rates, the deformation of the polymer chains is restricted to be (Figure 6). mobility of the polymer chain on the atomic and stretching of the chemical bonds, and the storage modulus of the rubber can increase by up to scale (rotations between molecular units) orders of magnitude. As a silicone bond is loaded, micro cracks will eventually start to and form and propa The same increase of performance is observed on the macroscopic scale (straightening of General Business for shear mode (Figure 7). the chain between cross-links). The strain rate intelligent glass solutions | summer 2021 General Business

elongate before the crack has propagated and hence reach higher elongation and strength principles for polymeric material predict that principles such low for polymeric glass transition material temperature predict that would suchalso lowresult, glass transition temperature would also r when loaded at conventional speeds.

under constant temperature, to a very stable under property constant profile temperature, under very to short a veryimpact stableload property conditions. profile under very short impact load condi

silicone sealants aretheory characterized by an the excellent retention ofGAINING their physical properties The is predicting particularly good The performance theory is TRACTION predicting of the silicone the particularly sealant when good performance submitted to of a the silicone sealant when submitted GLOBAL TECHNOLOGIES AND TRENDS broad temperature characteristic linkedfor to bomb the low hurricane glass very range. suddenThis load conditions istypical veryvery sudden blast, load transition conditions or earthquake. typical for Thebomb critical blast, point hurricane for a or earthquake. The critical point Tg) of the centralstructural polymer backbone silicone elastomer, that can reachsealant –120 °C.isThis low sealant isofto remain elastic and structural to keep its strength to and remain movement elastic and capability. to keepAny its glassy strength and movement capability. Any ed by the inherent flexibility of the polymer molecules and is typical and unique to silicone. behavior of the silicone sealant could lead behavior to cohesive of thefailure silicone of sealant the sealant. couldWith lead atopolymeric cohesive glass failure of the sealant. With a polymeric and, in particular, the Boltzman Superposition and for Time/Temperature Equivalence transition of –120 °C versusfor 20°C organic transition elastomer, of the –120 silicone versus is the 20°C for organic ofproposed choice elastomer, for suchthe silicone material sensitivity reflectstemp the timescale required leading to a temp deformation as°C illustrated in material calculation methodisisthe a worst case of choice fo polymeric material predict that such low glass transition temperature would also result, applications. theseapplications. polymer chain re-orientations to take Figure 8. Therefore in a simplistic (quasi-static) scenario due to its assumptions (e.g. frame t temperature, to a very stable property profile under very short impact load conditions. place. At low strain rates the polymer chains approach, the maximum force acting on the rigidity). In reality, systems can be optimized so predicting the particularly good performance of the silicone sealant when submitted to a have sufficient time to re-orient themselves sealant at the center of the long edge of the that the energy of the blast can be absorbed by oad conditions typical for bomb blast, hurricane or earthquake. The critical point for a and the storage modulus of the rubber is low. glass pane can be estimated by replacing the plastic deformation of the frame elements or Joint dimensioning methods Joint dimensioning ant is to remain elastic and to keep its strength and movement capability. Anymethods glassy At high strain rates, the deformation of the three-dimensional membrane with a twothe effect of the interlayer. e silicone sealant could lead to cohesive failure of the sealant. With a polymeric glass Some of the deformation conditions that the Some silicone of thecross sealant deformation experiences conditions canby be that approximately the silicone sealant derived.experiences can be approximately de polymer chains is restricted to bending and dimensional section, represented a p of –120 °C versus 20°C for organic elastomer, the silicone is the material of choice for such For aof 4-sided bonded glass For glass a “rope” 4-sided is broken, bonded theglass interlayer once a membrane. is broken, the interlayer behaves as a memb stretching the chemical bonds, and pane, the once the flexible fixed between twopane, pointsbehaves under theasglass Blast events are complex loading phenomena Assuming frame is infinitely rigid, stress Assuming will the beInmaximum frame is infinitely inthe the middle rigid, the of the stress long edge be of maximum the answers in the the long edge o storage modulusthe of the rubber can increase by the constant load. this model, load is acting andwill representative formiddle siliconeof joints and minimum in the pane to a and deformation minimum asin illustrated the leading Figure to 8. can aTherefore deformation in a as illustrated inthe Figure 8. Therefore up to pane three orders of magnitude. As acorner siliconeleadingperpendicular on the rope at anycorner pointin along only be obtained by simulating (quasi-static) simplistic force (quasi-static) acting on considerations theapproach, sealant atthe themaximum center of the long acting edge oninterlayer, the sealant at the center of the long bondsimplistic is loaded, micro cracks willapproach, eventuallythe maximum its length. Simple static allow fullforce system (glass, fixation, frame ning methods of the glass pane can be estimated by replacing of the the glass three-dimensional pane can be estimated membrane by replacing with a two-dimensional the three-dimensional membrane with a two-dimen start to form and propagate. The propagation derivation of the line load and its perpendicular structure). For instance, modeling of laminated cross section, represented by a flexible “rope” cross section, fixed between represented two points by a flexible under constant “rope” fixed load. between In this two points under constant load. I eformationaround conditions thatin the sealant can be approximately derived. the fillers thesilicone polymer matrixexperiences takes components at the fixation points and at the glass and its behaviour after breakage is model, the load is acting perpendicular model, on the the rope load at is any acting point perpendicular along its length. on the Simple rope static at any point along its length. Simple bonded glass pane, once glass isatbroken, the interlayer behaves as a membrane. time but if the jointthe is loaded high speed, center of the membrane, as follows not obvious and requires the knowledge of considerations allow of in thetheline considerations load of and perpendicular allow of the line at load the fixation and its perpendicular points components at the fixation p frame is infinitely rigid, the stress will derivation be maximum middle theitslong edge derivation of the components the chains can elongate before the crack has parameters difficult to estimate such as the and atleading the center the membrane, as follows and at the 8. center of theinmembrane, as follows imum in the corner to a of deformation as illustrated in Figure Therefore a propagated and"²hence higher elongation percentage of delamination of the glass shards % reach "² of%the long edge si-static) approach, the𝑝𝑝maximum acting on the sealant at 𝐻𝐻! = $$% − &than & force 𝐻𝐻!the = center 𝑝𝑝 $$% − & (1) and strength at failure when loaded at adhering to the interlayer. Considering(1) the & ne can be estimated by replacing the three-dimensional membrane with a two-dimensional '" '" conventional speeds. complexity of the problem and the influence (2) (2) represented by𝑉𝑉a! = flexible “rope” fixed between two points 𝑉𝑉under ! = &constant load. In this & of the various parameters, the above simple "² on% the rope at any point along its length. "² % ad is acting perpendicular Simple static 𝑄𝑄( = 𝑝𝑝 $ + & 𝑄𝑄( = 𝑝𝑝 $$% + && (3) (3) $% load & and its allow derivation of thesilicone line at the fixation points Furthermore, sealants areperpendicular characterized components analytical calculation methods should be used & & & & ter of the membrane, as follows 𝑄𝑄! = *𝐻𝐻! + 𝑉𝑉! = 𝑄𝑄( (4) by an𝑄𝑄 excellent retention of 𝑄𝑄 their with caution in the early design phases(4) of a ! = *𝐻𝐻 ( physical ! + 𝑉𝑉! = % )! +"% )! +"% properties along a very broad temperature project, to provide an approximate estimate & 𝛼𝛼 = arctan $ & = arctan " 𝛼𝛼 = (1) arctan $ & = arctan " (5) (5) & *! " ,+%² *! " ,+%² range. This characteristic is linked to the of the required joint dimension to sustain a (2) very low glass transition temperature (Tg) certain load. Finite Element Analysis can % With b the span (m), h the deformation of the thehmiddle (m), p the pressure load blast (kPa), Hthe Withmembrane b the spanin(m), the deformation of the membrane in 0 middle (m), p the pressure load (kP & (3) of the central polymer backbone of silicone With b the span (m), h the deformation of the be used as an alternative design method. & the horizontal line load on fixation (N/mm), theV0horizontal line load onon fixation (N/mm), V0 Qthe the vertical line load fixation (N/mm), vertical tension line load on fixation (N/mm), Qm the te m the 𝑉𝑉!& = 𝑄𝑄( elastomer, (4) that can reach –120 °C. This low membrane in the middle (m), p the pressure This well-known simulation method allows the resulting line load on the fixation and the a the resulting line load on the fixation and line load in the middle of the membrane line (N/mm), load in Q the middle of the membrane (N/mm), Q 0 0 ! Tg is"+"% determined by the inherent flexibility load (kPa), the horizontal line load on fixation evaluating strain and stress levels in silicone & = arctan (5) H0 angle directional angle of resulting load Q directional of resulting load Q . . 0 0 " ,+%² ! of the polymer molecules and is typical and (N/mm), V0 the vertical line load on fixation (N/ joints in complex systems or under complex unique to silicone. Viscoelasticity and, in mm), Q the tension line load in the middle of loading conditions. Extrapolating such methods n (m), h the deformation of the membrane in the middle (m), p the pressure load (kPa), H0 m particular, the Boltzman Superposition and the membrane (N/mm), Q the resulting line developed for conventional loading speeds of line load on fixation (N/mm), V0 the vertical line load on fixation (N/mm), Qm the tension 0 resulting line load the directional angle e middle of the membrane (N/mm), Q0 the Time/Temperature Equivalence principles loadon onthe thefixation fixation and a the 5mm/min to high speed complex loadings such le of resulting load Q0. material predict that such low for polymeric of resulting load Q0. as blast events is, however, not straightforward. glass transition temperature would also result, In a first step, adapted hyperelastic material under constant temperature, to a very stable Based on calculated line load values and an models based on sealant testing at high property profile under very short impact estimated sealant shear strength at high speed speed Business rates are needed. Second, the failure General Business General load conditions. The theory is predicting the load as described previously, a bite can be easily mechanism should be carefully studied to particularly good performance of the silicone determined. No safety factors are considered, ensure which parameter accurately represents sealant when submitted to very sudden load because bomb blast impact always destroys experimental validation under blast. Parameters conditions typical forGeneral bomb blast, hurricane or the element. The calculation model requests of importance under conventional loading Business earthquake. The critical point for a structural an assumption for glass deformation h. This might not be relevant under blast loading sealant is to remain elastic and to keep its depends on glass thickness, interlayers, glass anymore. Please contact Dow to review suitable strength and movement capability. Any glassy type (e.g. annealed versus tempered) and hyperelastic material models for DOWSIL™ behavior of the silicone sealant could lead to potential fracture pattern of glass type. The Silicone bonding sealants used in blast loading. cohesive failure of the sealant. With a polymeric glass transition temp of –120 °C versus 20°C for organic elastomer, the silicone is the material of choice for such applications.

Joint dimensioning methods Some of the deformation conditions that the silicone sealant experiences can be approximately derived. For a 4-sided bonded glass pane, once the glass is broken, the interlayer behaves as a membrane. Assuming the frame is infinitely rigid, the stress will be maximum in the middle of the long edge of the pane and minimum in the corner 98

Figure 8: assumed model for the approximated analytical equations

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Based on calculated line load values and an estimated sealant shear strength at hig

Reducing modulus can actually be beneficial for the overall performance of silicone sealants under blast events, as long as the tensile strength is maintained and hence the elongation at break. This is illustrated GLOBAL TECHNOLOGIES AND TRENDS GAINING The TRACTION in Figure 9 showing two identical joints of 50mmx8mm loaded under the same blast conditions. Von Mises stress developed in the high modulus sealant under maximum deformation reaches values which are several orders of magnitude larger than those in the sealant with half modulus.

Figure 9: Two joints of 50x8mm loaded with the same blast. The sealant on the right has a Young modulus which is half the

Figure 9: Two joints of 50x8mm loaded with the same blast. The sealant on the right has a Young modulus whichof is half modulusleft. of theThis sealant left. Thisin results in significantly lowerstress stress in in thethe sealant. modulus thethesealant results significantly lower sealant.

Besides the influence of the intrinsic material properties, it is possible to optimize the response of the

Design jointrecommendations by adapting its geometry. It is known that the aspect ratio and hence the thickness of a joint It isinfluences a common belief high strength and its that capacity to accommodate deformation (Descamps 2017, 2018). To illustrate this, Figure 9 modulus are the most desired parameters compares a sealant with 50mm bite and thickness of 15mm (aspect ratio 3) to the previous case (50mm x positively influencing the strength of a bonded 8mm, aspect 6), both connection. Modulus ratio values provided by having the same modulus. The maximum value of Von Mises stress is nearly halved (~5MPaareversus sealant manufacturers typically10MPa) derived for the 15mm thick joint. from stress-strain graphs through linearization of the curve. These values will be used for approximate analytical calculations as illustrated above. When the real behaviour is modelled using FEA and integrating the full hyperelastic material behavior of the sealant in the simulation, it appears that sealants showing a significantly larger linear modulus eventually Figure 10: 50mmx15mm experiencing the same blast load and having the same m develop very similar strain levels as sealants with Figure 10: 50mmx15mm experiencing the same blastratio) load and havingin the same moduluslower as Figure 9 left. in the sealant. (reducing aspect results significantly stress a lower linear modulus. This can be explained Increasing joint thickness (reducing aspect ratio) results in significantly lower stress in the sealant. by the fact that the bulk moduli are used in It is interesting to note that the joint bite is not the only criteria to c FEA and these values are much more similar but that joint thickness playstoanote critical role thethecapability o for different sealants due to the incompressible 9 showing two identical joints of 50mmx8mm It is also interesting that the biteon is not nature of silicone elastomers. The deflection of loaded under the same blast conditions. only criteria to consider when dimensioning glass panes bonded with both types of sealants The Von Mises stress developed in the high the joint but that thickness also plays a critical Conclusion is very similar confirming the equivalence in modulus sealant under maximum deformation role on the capability of the joint to sustain the Silicone is the preferred bonding solution when dealing with extre end application of these materials. The strain reaches values which are several orders of blast load. blast events, thanks to its optimal combination of strength developed in a lower strength sealant with a magnitude larger than Business those in the sealant with General Appropriate geometrical joint dimensioning guidelines can help higher elongation capacity will also be lower. half modulus. High moduli sealants typically have a lower Conclusion However, the complexity of blast loading phenomena require sealant deformation capacity as they have are Besides the influence of the intrinsic material Silicone is the preferred bonding whenthe beha methods to obtain representative results whensolution analyzing formulated with a higher filler content which properties, it is possible to optimize the dealing with extreme loading such as those which are representative of reality can only be obtained by simu can limit elongation at break. As described response of the joint by adapting its geometry. observed in blast events, thanks to its optimal framethestructure). Thisofimplies close collaboration betw previously, deformation levels reached by It is known that the aspectfixation, ratio and hence combination strengthaand movement interlayer and well as the façade consulta sealants under blast loadings are extreme and thickness of a joint influences its capacity to glass manufacturers, capability properties.asAppropriate geometrical a good movement accommodation capacity is accommodate deformation (Descamps 2017, joint dimensioning guidelines can help to be initiated as early as possible in the project to maximize the bene key to successful design. 2018). To illustrate this, Figure 9 compares a further optimize its performance. However, Dow is continuously developing expertise of blast loading. P sealant with 50mm bite and thickness of 15mm the complexity ofits blast loading phenomena Reducing modulus can actually be beneficial (aspect ratio 3) to the previous case (50mm x requires the use of advanced dimensioning Specialist to further discuss your project requirements for the overall performance of silicone 8mm, aspect ratio 6), both having the same methods to obtain representative results sealants under blast events, as long as the modulus. The maximum value of Von Mises when analyzing the behavior of silicone joints. tensile strength is maintained and hence the stress is nearly halved (~5MPa versus 10MPa) for Reaching results which are representative of References elongation at break. This is illustrated in Figure the 15mm thick joint. reality can only be obtained by simulating

ASTM C1135-19, Standard Test Method for Determining Tensile 99 Sealants intelligent (2019) glass solutions | summer 2021

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

the full system (glass, interlayer, fixation, frame structure). This implies a close collaboration between the system supplier, the sealant, interlayer and glass manufacturers, as well as the façade consultants. Project review and analysis should be initiated as early as possible in the project to maximize the benefits of the use of the silicone. Dow is continuously developing its expertise of blast loading. Please contact your Dow Technical Specialist to further discuss your project requirements References ASTM C1135-19, Standard Test Method for Determining Tensile Adhesion Properties of Structural Sealants (2019) Descamps P, Hayez V, Chabih M, Next generation calculation method for structural silicone joint dimensioning , Glass Struct. Eng. DOI 10.1007/s40940-017-0044-7 (2017) Descamps P, Dimensioning silicone joints used in bomb blast resistant facade systems, in Proceedings of Challenging Glass 6 (2018) Dewey J. M. ‘The shape of the blast wave: studies of the Friedlander equation’, 21st International Symposium on Military Aspects of Blast and Shock, Israel (2010) EOTA, ETAG002 Guideline for European technical approval for structural sealant glazing kits (2012)

Yarosh K, Wolf A, Sitte S "Evaluation of silicone sealants at high movement rates relevant to bomb mitigating window and curtainwall design." In Durability of Building and Construction Sealants and Adhesives: 3rd Volume. ASTM International, 2010. THIS INFORMATION IS OFFERED IN GOOD FAITH FOR YOUR CONSIDERATION, BUT WITHOUT GUARANTEE OR WARRANTY (EXPRESS OR IMPLIED), AS ANALYTICAL CONDITIONS AND METHODS OF USE OF THE INFORMATION AND MATERIALS DESCRIBED HEREIN MAY VARY AND ARE OUT OF DOW'S CONTROL. ALTHOUGH THIS INFORMATION IS BASED ON DATA DOW BELIEVES TO BE RELIABLE AND ACCURATE, WE DO NOT INTEND FOR YOU TO USE, AND YOU THEREFORE SHOULD NOT CONSTRUE, THE CONTENTS OF THIS DOCUMENT AS BUSINESS, TECHNICAL OR ANY OTHER FORM OF ADVICE. WE RECOMMEND YOU DETERMINE THE SUITABILITY OF THE INFORMATION AND MATERIALS DESCRIBED HEREIN BEFORE ADOPTING OR USING THEM ON A COMMERCIAL SCALE. DOW ASSUMES NO LIABILITY IN CONNECTION WITH THE USE OF THIS INFORMATION. Jon Kimberlain currently provides technical expertise and application support for Dow Silicones as a Senior Scientist. With Dow Corning and Dow, Jon has published 25+ research papers on the use of silicone sealants in high performance buildings presented at venues such as Façade Tectonics, ASTM, and GPD Finland. Currently a founding board member of Architectural Glass and Metal Certification Council, he has also been active in GANA and NGA.

Hautekeer JP, Monga F, Giesecke A, Brien BO: The use of silicone sealants in protective glazing applications. Glass processing days conference proceedings pp 298-302 (2001) Kranzer, C., Gürke, G., and Mayrhofer, C., “Testing of Bomb Resistant Glazing Systems Experimental Investigation of the Time Dependent Deflection of Blast Loaded 7.5 mm Laminated Glass,” In Glass Processing Days Proceedings, J. Vitkala (Ed.), Tamglass Oy, Tampere, Finland, pp. 497-503; available online at: http://findarticles.com/ . (2005) Mueller R, Wagner M, Berechnunng explosionshemmender Fenster- une Fassadenkonstruktionen, IBDRM (2006)

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Valérie Hayez is Global Façade Engineering & Architectural Design Engineer for High Performance Building Solutions at Dow based in Belgium. She provides technical service to the design community, including façade system manufacturers, architects and engineers and communicates industry needs to Dow‘s Research and Development Community. Valérie has developed a broad expertise in façade engineering, including structural performance, fire safety, thermal or acoustic insulation and is active at standardization level. She holds an MSc and a PhD in Applied Sciences (electronics and optics) from the University of Brussels.

Sigurd Sitte is Senior Technical Service & Development Scientist for High Performance Building Solutions at Dow in Germany. He has over 25 years providing expertise to architects, consultants and glass industry professionals on silicones applied in curtain wall and glass applications as well as solar. Sigurd also represents Dow in several research projects with test institutes and universities and coaches global projects with glass and facade applications.

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

Water-filled Glass (WFG):

New opportunities in glass construction

Dr Matyas Gutai Lecturer at Loughborough University Founder, Water-filled Glass Ltd. Water House 2.0 Pavilion built in campus of Feng Chia University in Taichung, Taiwan

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lass is an essential material for buildings and a real challenge in sustainable construction. Regardless of its proportion on building façade, it is responsible for at least 25-35% of heating-cooling energy demand in buildings. As an option for energy renovation or retrofit, improving glass properties has a great potential not just because its disproportionate impact on energy consumption: it is also a universal solution that can be effectively applied to any climate (hot or cold), for any project (newbuild or retrofit), any function or type of building (e.g., historical or modern building). If we consider the flexibility of glass improvements for any building and the scale of environmental impact of glass on buildings (greenhouse gas emissions of glass related heating-cooling in buildings is equal to all emissions of road transport globally or 40% of all road transport), it is easy to see that any opportunity of improving glass in buildings has significant impact on our chances to fight climate change. The current strategies for improving glass on building envelopes (windows, curtain walls, skylights etc.) is typically improving insulation or U-value (e.g., adding more glass layers), improving absorption-reflection or G-value/ SHGC or using some kind of shading. Waterfilled Glass or WFG presents a fourth option where energy performance is improved by using a fluid medium in the insulated glass unit or IGU. Water improves absorption of the window (which lowers energy demand) and transfers the captured heat to a thermal storage for later use. The solution has several advantages: Firstly, it improves colour retention of glass simply because water is an optically transparent layer: it absorbs heat in the invisible spectrum of radiation therefore it improves absorption of glass without any visible impact on its transparency. WFG provides low SHGC values even with clear glass, which brings a functional and aesthetic benefit since energy retention would normally compromise appearance (clarity) of glass on buildings. Secondly, it provides healthier indoor environment by controlling surface temperature of glass, which lowers the need for air-conditioning, a clear asset for thermal comfort, indoor air quality and infection risks (through ventilation). 102

Water House 2.0 Pavilion, south façade. Water-filled Glass (WFG) was used to capture radiation gain and protect indoors and protect indoors from overheating without shading or tinting of glass. This provided clear view towards the lake without compromise on thermal comfort.

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Thirdly, the technology saves a considerable amount of energy: considering equatorial orientation, WFG 47-72% compared to double glass (U=1.4 W/m2K), 34-61% compared to triple glass (U=1.2 W/m2K) and 23-66% compared to solar protection glazing or electrochromic glass. This energy performance is achieved by a new energy model, which we will introduce in the next chapters below.

Axonometric diagram of Water-filled Glass (WFG) general detail. The technology is applicable with existing construction systems. In this particular case, we used Schüco frame as an example.

Fourthly, in addition to the energy savings above, WFG also works as a solar thermal collector that not only absorbs but also utilizes solar energy. This is a real advantage for buildings with large glass surfaces (especially with smaller roof area) even if WFG’s efficiency for capturing solar energy is lower than conventional solar thermal collectors. The fifth benefit of WFG is its high sound attenuation as the technology absorbs sound and blocks noise from exterior better than standard IGUs. The sixth advantage of WFG is lowering construction cost for new buildings because the cost of mechanical system drops as WFG reduces energy demand of the building. The seventh benefit of WFG is being a patented and sustainable solution that supports energy accreditations as an innovative technology.

Water House 2.0 with context. As the surrounding buildings show, solar gain is high in Taichung which requires intensive shading to protect indoors. This shading was replaced with the water layer in WFG, which absorbed the heat and removed it to a thermal storage for later use.

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Finally, the last benefit of WFG is achieving all of these without an increase in embodied energy or carbon of the product, which keeps the environmental impact of the construction low, which gives a good advantage compared to latest glass innovations like Building Integrated Photovoltaics or electrochromic glass. These benefits combined together present a competitive technology especially considering that WFG comes with a construction cost that is comparable to standard triple glass construction. Still, with all these advantages, the question may arise whether this technology is viable and a simple thin water layer in an IGU can make so much difference? The key in the answer lies in a way WFG operates: the result comes not from placing water in the glass but by allowing it to move.

Axonometric diagram of Water-filled Glass (WFG) bottom detail. The system requires minimum amount of pipework, which is hidden in the floor. The components (pump, pipes, etc.) are existing off-shelf products.

The first prototypes of WFG were produced ten years ago in collaboration with Guardian Glass and Jüllich Glas. Since then, the technology went through long process of testing, monitoring and simulation.

Energy retention and conditioning vs. distribution Glass in buildings is evaluated through U-value and SHGC. This makes absolute sense since standard glass in buildings are made of solid materials: their properties are constant in time and their energy exchange capacity (e.g. moving energy between building parts) is limited compared to fluids. From this perspective a Water-filled Glass or WFG does not make much of a difference in energy performance: a thin water layer would absorb some of the radiation but would heat up quickly. If the water layer is replaced with an argon layer, the glass would have better U-value which would quickly compensate for the lost absorption even if there is a way to reuse the captured heat. Water in the glass could be heated/cooled with a more effective mechanical solution than the current heatingcooling in the building, which may lead to energy savings on its own. Still, this would require more investment and the amount of savings would not be significant compared to

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Interior image of Water House 2.0. The water infill and flow has no effect on transparency, the glass retains clear view without need for coloring or shading as the water protects indoors from overheating.

Conventional glass cannot control solar gain and heat enters indoors, which leads to overheating and greenhouse effect. Water-filled Glass (WFG) absorbs heat in the invisible spectrum of radiation therefore it improves SHGC without impact in view or colour retention. The absorbed energy is transferred to ground or thermal storage for later use.

a window with better U-value. This is all true of course: absorption of water is just a small proportion of WFG’s energy savings. Most of the savings come from the energy exchange or distribution resulted by the water flow, which takes advantage of the fact that WFG is not a solid but a hybrid structure. To explain this let us look at a simple example: a house with a glass extension looking towards 106

south, which would be a typical conservatory. On a typical summer day, the glass space would require cooling while domestic hot water supply in the house would need heat. Our current response for this would be to spend electricity for both: cooling in the space and heating for the boiler. Let us imagine an alternative and assume that we are able to connect the two energy demands: take heat from glass space/conservatory (which

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is cooling) and give it to the boiler. In such case the energy demand for both would drop before any mechanical system would turn on. This is the significant difference of WFG compared to any other structure: it enables us to move energy effectively to lower energy demand before consumption would occur. Doing so WFG recognises a simple rule when it comes to conditioning vs. distribution: moving 1kW heat from one place to another takes up to

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

World map with the 13 cities that were evaluated for WFG façade. The cities cover all major climates globally: Tropical, Dry, Continental, Temperate and Polar.

Energy savings with WFG in the selected cities compared to Double Glass window (U=1.4 W/m2K+Low-E) and Triple Glass (U=1.2 W/m2K+Low-E).

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Hourly performance with WFG in different climates. The graphs show that WFG lowers operational temperature and energy demand significantly. The results were published in detail in our publication titled ‘Energy consumption of water-filled glass (WFG) hybrid building envelope’ in Energy and Buildings journal. (Link: https://www.sciencedirect.com/science/article/abs/pii/S0378778819328944?via%3Dihub)

10 times less energy than heat the actual space with mechanical system. This can be increased further: if we move heat from a location that requires cooling to an area that needs heating than our saving doubles and we spent up to 20 times less energy to heat and cool these spaces compared to using the mechanical system in each room. This is why when we design energy strategy for buildings with WFG we always look at the energy demands holistically and identify 108

opportunities to lower energy demand before relying on the mechanical system. This can be ground or another part of the building, depending on the energy profile of the project. To explain our energy model and design approach we often use the example of ‘conditioning the Moon’ like we would do with a building: the logical response would be to cool the side with solar gain and heat the other to maintain comfortable temperature. Our energy consumption for such project would be determined by our energy retention (this case

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insulation and thermal mass) and the efficiency of our mechanical system (conditioning). Our approach with WFG is more like Earth, where we rely on retention (insulation and thermal mass) and add distribution (of water) to lower energy demand before conditioning (mechanical system). Our approach does not conflict with Envelope First Approach: it builds on it and enhances it further. This is what the title with ‘new opportunities in glass construction’ refers to and what we mean with by saying that WFG can turn

GLOBAL TECHNOLOGIES AND TRENDS GAINING TRACTION

Water House 1.0 was build as the first experimental building for WFG concept in Kecskemet Hungary. The building explored various cases of glass construction including glass corner and skylight with WFG.

glass from a liability to an opportunity: today energy demand is a problem that is resolved individually (e.g. in each room is isolated in the building), while in the future energy demand is an opportunity to resolve issues collectively (e.g. rooms with opposite demand sharing energy). This approach results in the energy savings and improvements of thermal comfort that is outlined in the chapters below in detail. Developing Water-filled Glass (WFG) technology The development of WFG technology started in 2007 at The University of Tokyo in the laboratory of Prof. Kazuhiko Namba as a PhD research of the author. The research later continued in the same university at the laboratory of Prof. Kengo Kuma as a postdoctoral research and after that at Feng Chia University in Taiwan and at Loughborough University in the UK. From the beginning the project was a close collaboration with enterprises, in particular with Guardian Glass and Jullich Glas in Hungary. The

Water House 2.0 in Taichung, Taiwan. The south facing glass façade with WFG was used to capture heat and move it either to other parts of the building envelope (roof, opposite wall, floor) or to the thermal storage.

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Thermal comfort example for Rome. The graphs show outdoor temperature (top), indoor temperature with double glass (middle) and with WFG (bottom). The results show that WFG lowered cooling load in summer and increased heating effect in spring. Both was a desired outcome and was managed by changing the water flow, which presents that the performance of WFG can always be tailored to specific needs.

manufacturing process of WFG was developed based on existing glass production techniques to make sure that glass factories can adapt to the technology easily. This became an asset today as we now are expanding the network of glass manufacturers worldwide. This aspect was also beneficial in embodied energy/carbon of WFG: new products require new machinery and factory, which keeps the embodied energy/carbon level of the product high until production reaches global scale. This does not apply to WFG, which effectively becomes one of the products that the glass manufacturer can produce. This and its material use (WFG differs from a triple glass essentially in water infill) keeps the carbon level of the product low. Another early challenge of WFG development was viability of the product and its construction process. This was effectively mitigated by using existing technologies whenever possible, including pumps, pipes and structural framework, which kept the construction process simple and easy to 110

adapt for any project. As a result the final WFG can be effectively combined with existing technologies both in terms of mechanical systems and methods of construction. The challenges of this process including risks mitigation of WFG are outlined in the publication “Construction Aspects of Hybrid Water-Filled Building Envelopes” (link for Open Access: https://journals.open.tudelft.nl/jfde/ article/view/4784). This process ended with the construction of Water House 01 and Water House 02, which are introduced in the next chapter. The energy consumption aspects of the technology were evaluated based on the tests conducted on the Water House projects, which were the basis for a new simulation method tailored for WFG envelopes for TRNSYS. The technology was tested in a global simulation for 13 cities. The energy model utilised assumed that WFG is connected to the ground, which acted as both heater and cooler depending on the energy demand. The evaluation presented

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energy savings in all climates: tropical (BrasiliaBR, Singapore-SIN), dry (Tehran-IR, Torrence-US), continental (Beijing-CHN, Debrecen-HU) and temperate (Tokyo-JPN, Shanghai-CHN, New York-US, Sao Paulo-BR, Srinagar-IN, MannheimDE). The results show that WFG technology saves energy effectively in all inhabited climates and works well in both hot and cold regions. The reason for this is the local ground temperature that heats WFG in winter and cools it in summer. The energy savings very depending on climate and fall between 47-72% compared to double glass (U=1.9 W/m2K), 34-61% for triple glass (U=1.0 W/m2K) and 23-66% for both solar protection glass or electrochromic glass. The savings here indicated does not include the savings from the captured heat and generated hot water which can lower energy consumption even further (e.g., reused for heating or hot water supply). The details of the energy model and simulation of WFG is presented in the publication titled “Energy consumption of water-filled glass (WFG) hybrid building envelope” (Link: https:// www.sciencedirect.com/science/article/abs/

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The chart shows performance of WFG compared to double glass (shown as BS0, U=1.4 W/m2K), double glass with automated shading (shown as BS1, U=1.4 W/m2K) and triple glass (shown as WF0, U=1.2 W/m2K). WFG is presented with two examples, a thin (shown as WF1) and a thick water layer (shown as WF2). The graph shows 13 cities that covered all inhabited climates globally. The results show that WFG saves energy in all climates effectively except in polar climates (FLK Mount Pleasant). In some cases the heat captured of WFG could be reused for heating. This is not included in the energy savings but is shown here as Quseful (green). The results presented here were published in detail in our publication titled ‘Energy consumption of water-filled glass (WFG) hybrid building envelope’ in Energy and Buildings journal. (Link: https://www.sciencedirect.com/science/article/abs/pii/S0378778819328944?via%3Dihub)

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Water-filled Glass (WFG) prototype. As the image shows, WFG has the benefit of absorption in invisible spectrum of radiation, which improves SHGC while keeping the class optically clear. This keeps good color retention and view without compromise on energy consumption or thermal comfort.

pii/S0378778819328944?via%3Dihub) for transparent WFG. For color changing or ‘smart water-filled glass” (SWFG), the energy savings are presented in the publication “Energy consumption of hybrid smart water-filled glass (SWFG) building envelope” (Link: https://www. sciencedirect.com/science/article/abs/pii/ S0378778820306812). In addition to energy savings, WFG also improves thermal comfort in buildings. Our studies have shown that the comfortable hours per year increase with WFG by 14-23% compared to double glass, 3-23% compared to solar protection glass and 14-23% compared to electrochromic glass. The figures below show the PMV values for a case in Rome. As the results show, WFG lowers chances of overheating in the summer and enables overheating in spring, which is a desirable outcome for this case. This also shows that 112

the performance of WFG is not constant in time but can be always tailored to the time of the year and to the aim of the design: WFG can protect a space in particular time of the year and overheat the same space in another period depending the preference of the building. Water House 1.0 and Water House 2.0 Water House 1.0 was built as the first building based on the new energy model of WFG, which case the majority of energy savings were not achieved through energy retention (insulation, thermal mass) or efficient mechanical system but through energy distribution. The experimental building was titled ‘Water House’ based on the novel characteristic of the building envelope: the envelope consisted of prefabricated opaque and transparent panels, which were connected in a ‘water loop’ to enable water

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Entrance of the Water House 2.0

flow between panels and around the cross section of the building. These loops were connected to a thermal storage that absorbed heat surplus during cooling periods and provided heat in case of heating demand. Additional heating-cooling was provided by reversible heat pump when the storage was insufficient to cover demand. The building had a relatively high window-to-wall-area ratio (WWR), with large openings toward south to increase heat gain because the captured heat was later used for heating the building (seasonal storage). Energy exchange or distribution between building and storage benefitted the structure twice: once during cooling (removing heat from the building) and twice for heating (using the same heat to reheat the structure). The panel connections and water flow were designed along three water loops to facilitate energy exchange

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Dr Matyas Gutai is a Lecturer (Asst. Prof.) at Loughborough University and founder of Water-filled Glass Ltd. He graduated as MArch at Budapest University of Technology and Economics and as MEng at The University of Tokyo, where he wrote his PhD on Water-filled Glass and Advanced Hybrid Building Envelopes. He worked as an architect in various offices including Shigeru Ban Associates. As an academic, he was JSPS Postdoctoral Fellow at Kengo Kuma Lab at The University of Tokyo and taught at Budapest University of Technology and at Feng Chia University before joining Loughborough University. His practical and academic work focuses on Advanced Facade Design and Engineering, with specific focus on water-filled glass technology and other responsive advanced building envelopes.

Exploded axonometric of Water House 2.0

Detail diagram of WFG panels.

between north-south façades. These loops became the basic unit for larger projects later on because the same loops can be stacked in a building increasing water pressure or challenge in construction.

that WFG can effectively operate already in transparent state and lower energy demand significantly by simply allowing water flow within the building or between building and its external thermal storage.

The same type of loop structure was established in the second project titled ‘Water House 2.0’, which was built in Taichung, Taiwan. The project was built without standard shading or insulation, which increased the radiation load of indoors significantly. The geometry of the building was determined based on solar gain and followed a shape that resulted in high gain on south side and minimal one on north. This was important to establish temperature difference between the two sides, which supported water flow from hot areas towards colder ones and also enabled radiation cooling of north panels and floor towards outside. The energy performance of the building showed

Conclusion The first experimental buildings with Waterfilled Glass (WFG) titled Water Houses proved the viability of WFG technology. Since then, a team of three colleagues, Abolfazl Ganji Kheybari, Daniel Schinagl and Matyas Gutai founded Water-Filled Glass Ltd to collaborate with industrial partners (glass factories, construction companies, engineers, architects) globally on this novel approach of sustainable design and glass construction. After long research and testing, the next steps in the development of WFG will be the first pilot projects that will push our vision of new type of energy-efficient glass construction

through energy distribution with water and hybrid construction. We always welcome opportunities for feedback or engage with new projects regardless their function, scale or location. Please visit our Linkedin page or our website www.waterfilledglass.com for more information. Acknowledgement WFG team would like to express their gratitude for the kind support of universities and companies over the years, in particular to Jülich Glas (HU), Guardian Glas (HU), Hesung Construction (TW), AGC Glass (JP), The University of Tokyo (JP), Feng Chia University (TW), Budapest University of Technology (HU) and Loughborough University (UK).

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Capital C, geometric optimization of a free steel gridshell toward quadrilateral glass un

Koos Fritzsche a, Wouter van der Sluis a, Erik Smits b, Jack Bakker b a Octatube, The Netherlands, k.fritzsche@octatube.nl b ZJA, the Netherlands, es@zja.nl

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he former Diamond-exchange building in Amsterdam, now called Capital C, is restored to its former glory. This listed building has been returned to its original design and topped with a spatial gridshell roof structure of glass and steel, designed by renowned architectural studio ZJA. This paper focuses on the geometric optimization of the free-form gridshell towards planar quad glass units.

e-form ds planar nits

The final shape of the gridshell is determined by a parametric computer model. With a by ZJA in-house written program, the boundary conditions were defined, after which the software searches the ideal shape. In the case of Capital C, the ideal shape was a geometrical free-form shape but with planar or minimal curved quadrilateral glass. This to represent the faceted aesthetics of the diamond, representing the building’s heritage. In addition to the look, optimizing to planar glass panes also increased the feasibility and cost-efficiency of the design. During this process Octatube, as a specialist Design and Build contractor, was approached and challenged to realize this innovative and complex design. In principle the gridshell has one repetitive structural steel connection. However due to its shape every connection is unique and itself composed of many unique parts. In the final design, approximately 1000 different steel elements and 200 different glass units are applied. With a traditional design method, where all elements are modelled one by one, a minor change to the geometric shape of the shell would lead to a large amount of labour. A timeconsuming and error-prone job. Therefore the design is automated, by means of an in-house developed parametric tool by Octatube, which converts the complex basic geometry into a FEM-model and detailed production model. The applied methods of parametric design and engineering allowed the team to not only optimize the glass-design until late in the engineering phase, incorporating a file-tofactory workflow, it also allowed for fast and very precise pre-fabrication. Not unimportant when installing a free-form glass and steel gridshell on top of a listed building in the heart of Amsterdam. Fig.14 the Diamond Exchange, Capital C, 2019. Photo by Jan Willem Kaldenbach.

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Fig. 1a) The Diamantbeurs in 1911, b) 1983 and c) 1990

1. Background As a building and as an institution the Diamond Exchange, built in 1911 after a design by Gerrit van Arkel, crowned the heyday that counted as a second Golden Age for the city of Amsterdam: the economic boom following the 1880s, that restored the city as a metropolis for industry and trade.

However, at the beginning of the 21st century, the building was in a poor state. After several additions, a fire and various renovations much of the original charisma was gone (fig. 1) A thorough renovation was called for and ZJA were asked to produce the design with three objectives: First of all, to restore the original

Fig. 2 the Diamond Exchange, Capital C, 2019. Photo by Capital C.

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qualities of the Diamond Exchange in its full glory. Secondly to adapt the interior for use as a modern, flexible office environment and thirdly to build a contemporary addition open to the public. That addition, an event space and terrace on the seventh floor, under an oblong dome, is the subject of this paper (fig. 2).

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Since many of the constraints put on the dome (available floor area, materials used etc.) were given from the onset, a thorough, methodical search through the available design space could be performed. The structure of paragraphs 2-4 more or less faithfully reflect the chronology of that search. After the development of the principle design, Octatube was challenged to further develop the technical detailed design, optimization of steel structure detailing and the production methodology of the gridshell. The steps taken towards the final manufacture and installation of the rooftop build-up are described in paragraph 5-9. 2. Choice of glazing system During the whole design process, the glass geometry has been the leading consideration. It was assumed that a suitable steel structure could always be found for any sensible glass geometry.

Also, in a very early stage, a triangulated geometry was ruled out for aesthetic reasons. The overall geometry would consist of quads, with possibly some triangular panels in special places. Besides the rectangular overall geometry of the glass, the way this glass would geometrically follow the curved dome was an essential boundary condition for the further design. Four options, each with their own pros and cons, were considered: • Double curved glass; • Single curved of constant radius; • Planar quad panels, with offsets between edges of adjacent panels; • Planar quads with flush edges. 2.1. Double curved Clearly double curved glazing comes closest to approaching a free-form, smooth oblong dome. However, it is also by far the most expensive option, more so because the geometry allows for little repetition in the shape of individual panels, so reuse of moulds is not possible. It was therefore ruled out on cost grounds. 2.2. Single curved The principle of the single curved option is that each panel is assumed to be cylindrical, with constant curvature. For each individual panel the bending radius and the bending

axis are decided by measuring the curvature of the underlying, smooth reference surface at the panel centre. The radius is then set to the principle curvature direction with the smallest radius, the bending axis aligns with the other principle curvature direction. This works well for the middle part of the dome which is more or less cylindrical: bending axis and radii of adjacent panels match up, leaving no gaps between panels. The ends of the dome however are more or less spherical. Here the principle curvature direction of adjacent panels, and therefore the edges of the panels, will in general not align. This difference in edge shape can be taken up by adding framing with sufficient depth, that hides this discrepancy, but that would clash with the desire to have an uninterrupted exterior. Moreover, since the bending axis differ from one panel to the next, reflections in the glass tend to emphasize the shortcomings (see fig. 3). It was therefore not our favoured option. 2.3. Planar with edge offsets Panels are laid out next to each other, without any need for the edges to align. While three planes always intersect in one point, but four planes generally do not. This results in gaps between panels, that can be filled with some form of framing. The result is a ‘scaled’ appearance (fig. 4).

Fig. 3 Single curved. Perfectly smooth in the cylindrical middle part of the dome, but showing defects in double curved regions.

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Fig. 4 Planar with edge offsets.

3. Topology and geometry For its aesthetic qualities, lower cost and simplicity of the detailing, planar glass panels with flush edges was our preferred option. This choice for the local glass geometry means that the final design will be an approximation of the smooth, idealized version of the reference shape we set out to achieve. The challenge was to match the topology and geometry of the design as closely as possible. Looking at the glass surface as a quadrilateral mesh, it can be further broken down to edges and vertices, the elements wherein the curvature of the shape is concentrated. For the edges following this geometry is not a problem: two adjacent faces meet at an angle and intersect in a straight line, giving the glass panes straight edges. Which is exactly what we want. The problem arises with the vertices. The majority of the mesh vertices will have valence 4, meaning that at each vertex 4 planes will meet. Now, whereas 3 (non-parallel) planes always intersect in one single vertex, 4 planes generally do not. We can fix this problem in one spot by changing the geometry slightly, but it then tends to pop up at some other vertex. It is a problem that cannot be solved locally. It has to be done globally, moving every vertex in the mesh in small increments, trying to conform to all the constraints at once.

Fig. 5 Planar with flush edges. Note that in this iteration the boundary vertices were restricted to stay on the perimeter. This constraint was later dropped. By allowing the faces to flow over the edge, the squeezed faces in the middle part were eliminated.

3.1. Topology drives geometry The topology of a mesh is defined by the connectivity of its vertices and faces, regardless of dimensions. It determines the number of faces that meet at the vertices. Not every mesh topology lends itself equally well to be optimized towards the desired shape. For the mesh to have a good chance to satisfy all constraints it must have a topology that naturally fits the reference shape, in our case an oblong, tube-like surface with spherical ends. Geometrically this is the easiest method to implement, since hardly any constraints are placed on the orientation of the glass. It does however add complicated detailing of the framing and a very specific aesthetic. It was rejected on those grounds. 2.4. Planar with flush edges In a way this option is the opposite of the previous. It is harder to develop the proper geometry because of strict constraints: panels must not only be planar, but all panels 118

surrounding a vertex have to intersect in one vertex as well. And where the former option needs intricate detailing, for this one a simple seam between the flush edges of panels will suffice. Paradoxically, even though a solution with planar panels seems, at least in principle, less smooth than one with single curved glass, the overall appearance of the planar panels looks like a better approximation of the smooth reference geometry (compare fig. 3 and 5).

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The trick is therefore to come up with a mesh topology that naturally fits our intended geometry. 3.2. Curvature through singularities One view of curvature is to regard it as a local deficit or excess of surface area. This is illustrated in fig. 6. If we assume faces to be planar and more or less rectangular, then fitting 4 of them together

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Both topologies (see fig. 7), nicknamed ‘roof’ and ‘box’, proofed to converge to a good planar geometry that met all constraints. In both cases orthogonality along the edges aids with creating the necessary opening for the terrace. The orientation change of the ‘roof option’ introduces a contrast between the long and short ends of the dome, having more visual appeal, leading to this geometry to be finally chosen. 3.4. Grid density With the choice of the singularities fixed, there remains only one free parameter for the mesh topology: the number of regular, valence 4, vertices between the singularities. This number will eventually decide the edge size of the panels after optimization. A lower density grid will not only have bigger panels, but also greater kink angles between them.

Fig. 6 The ‘natural’ geometry for vertices with a) valence 3, b) valence 4 and c) valence 5 or more.

Fig. 7 Topology with 2 singularities (‘roof’) resp. 4 singularities (‘box’). Two singularities has the added side-effect of rotating the grid orientation by 45 degrees.

leads to a geometry that naturally lies flat. Fitting three together, effectively taking away a quarter of the surface area, naturally forms a convex, synclastic geometry. And fitting 5 (or more) creates an excess of surface area around the central vertex, producing a wavy, anticlastic geometry (a vertex that has N surrounding faces, is said to valence N. If the valence of a vertex is not 4, it is called a singularity). Since the sides of our dome are approximately cylindrical, they have almost zero Gaussian curvature. So, although they are (extrinsically) curved, they are intrinsically flat. This means that vertices along the sides should have valence four.

ends of the dome the situation is different: since every direction on a sphere is a principle curvature direction, there is no preferred orientation for the edges in those regions. 3.3. Final mesh topology All these considerations left us with two natural candidates for the mesh topology. • two valence three vertices, one at each end: roof-shaped • four valence three vertices, two at each end: box-shaped

Both ends of the dome are spherical, so have positive Gaussian curvature. To facilitate, one or more vertices with valence three must be added to the mesh topology here.

Apart from having a different number of singularities, they differ in one important regard: in the box-shaped variant all edges run moreor-less horizontal or vertical. In the roof-option however, the topology forces the orientation of the panels to flip from orthogonal down the sides of the dome, to diagonal at the ends.

When optimizing towards planarity, mesh edges tend to align to the principle curvature directions. In the cylindrical middle part, we therefore expect the edges to become horizontally/vertically oriented. At the spherical

As already mentioned, the ends of the dome are spherical so every direction is basically a principle curvature direction. A diagonal pattern should therefore work equally well here as an orthogonal one.

Since the glass edges must align with the top and sides of the terrace opening, an integral number of panels must fit in this opening, in width as well as in height. This, along with transportation and production considerations, leaves only a small number of options for the grid density and more or less dictates the size of the panels. 4. Solving With all the boundary conditions defined, solving was done in Grasshopper/ Rhinoceros (Rhino) and the Kangaroo plug-in with the help of some custom written goals. Apart from the considerations mentioned above, a number of additional constraints were formulated. To summarize all of them: • Flatness: Each mesh face must be planar, which is measured as the distance between the diagonals of a face, divided by the length of the diagonals. This is constantly monitored while the solver is running by colouring mesh faces based this value. A face was considered to be planar if the planarity value was below 0.001. • Closeness to reference surface: This is not an absolute requirement, the mesh is allowed to take on a slightly different shape than the reference shape, as long as the net available floorspace and height don’t suffer. • Usable floor area: A minimum was set to the net floor area. • Minimum usable height: Closely related to the previous constraint, both the client and building regulations prescribed a minimal height. Effectively this constraint drove the optimization to a slightly more ‘boxy’ shape than would otherwise have evolved.

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Fig. 8 colours indicate planarity a) before relaxation, b) during relaxation c) final, planar result before trimming the boundaries d) after trimming

• Maximum building height: Municipal regulations set a maximum to the overall building height. • Squareness: Ideally, the glass panels have more or less square angles and equal edge lengths. This is not a hard constraint either, because enforcing it would not allow for any double curvature in the overall shape. • Smoothness: Edges that run in the same direction should not zig-zag, but should be more or less co-linear. • Symmetry: The dome has two symmetry planes, vertices on either side must remain mirrored over those planes. This is an absolute condition. • Uniform edge length: Together with the squareness goal, this ensures that panels will be of approximately equal size. • Align edges with the terrace: Since an opening would be made in the dome for the terrace, vertices surrounding the terrace area had to sit on three pre-defined planes, two for the sides, one for the top. Some of these goals tend to evolve the mesh in the same direction. Some however do not and conflict with each other. The outcome is a compromise between the different constraints. 120

Finding the proper balance between them is a process of trial and error. The process of solving is now straightforward. First a mesh is created with the appropriate topology and density. It is dimensioned so that it sits roughly in the right spot on the reference surface. Since it not known a priori how many faces are needed to cover the required surface area, the initial mesh was given some extra rows of faces at the bottom. At the same time the reference surface was extended downward to give the mesh ample room to run past the intended bottom perimeter. Any excess was trimmed off after the relaxation had converged. Then the solver is run, monitoring flatness and adjusting weights between the various constraints as needed. As said, this is a process of trial and error, especially given the relatively large number of constraints. Once the mesh geometry satisfied all objective and aesthetic criteria cut-outs for the terrace, back wall etc. were made. The resulting mesh describes the system lines of the glass geometry. This was then handed over to Octatube to develop the

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detailed design for the glass and steel structure. See figure 8 for the process of geometry optimization. 5. Parametric technical design Because of the free form of the design, all the parts (steel beams, glass panels, etc.) are unique and come together in different geometric ways. If anything in the design was adjusted, all parts changed. After all, everything was connected. At handover to Octatube, the basic geometry was given, but the grid was still under development. This situation raised the following question: How can the technical drawings be efficiently set up and the production prepared, before the basic geometry is established? From this challenge the idea evolved to automate the design by developing a parametric tool that could convert the complex basic geometry into a detailed production model. The design was parametrically designed down to the last detail and from these models the productions were managed. By designing the project parametrically, the construction proved to be not only technically feasible but cost effective as well.

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Fig. 9 Parametric tools a) line- and node-model in Rhinoceros, b) model translated to Inventor

5.1. Parametric tool In order to engineer the complex project, a flexible technical software package is required to allow for the unique elements to be modelled efficiently. Within Octatube, Inventor, an Autodesk modelling program, is used in combination with Rhinoceros (Rhino) and Grasshopper. Within this program a tool has been developed by Octatube that can export the wire model to Inventor (fig. 9). This parametric tool offers opportunities to play with geometry interactively and in a relatively simple way. By setting up the geometry parametrically, all properties remain continuously adaptable. One of the simplifications this provides is the possibility to develop variants. A model in Rhino actually consists of points and lines, a schematic representation of the actual construction or geometry: the lines are the beams and the points are the joints. Properties such as profile dimensions and materialization are linked to these elements. After the variant study and optimization, the tool automatically creates all the parts required for production. The great thing about this design process is that you don't have to start over and over again if something has changed. All you have to do is take the piece that needs to be changed. The most common, regular parts are done with the tool, but other, more complex parts and connection points are not. If you start programming every exception, it becomes too complicated. Normally you make 4 bars and 1 node with all the complexity in it, but in this design process we succeeded to make nodefree connections that looked more elegant.

In the end, we designed 9 different types of beams, see figure 10. They differ from each other because of the different connections. The engineer determines in the system where the various connection points will be located, which is the first step. The second step is the manufacturing of the beams and in the third step the building components are grouped and then assembled. 6. Structural analysis 6.1. FEM model In addition to the technical and production details, also the structural system and loads on the structure are generated through an in-house developed parametric link between Rhino and RFEM via Excel. Thereby maintaining the same flexibility in the definition of the grid during structural development. This allowed the structural optimization of the steel structure to best support the glass in the final developed geometry. The gridshell is supported by a steel construction by third parties which is placed

on the existing roof. An IFC export from the main structural engineer Pieters Bouwtechniek was used to provide the correct rigidity of the supporting steel structure with regard to the support points of the gridshell. 6.2. FEM Analysis With calculations from RFEM and IDEA Statica the dimensions of tubes (RHS) have been validated. Because the rotational stiffness of the connections is important for the stiffness and strength of the gridshell as a whole, two models were used. These two models represent respectively the lower and upper limits of stiffness of the connections and thus gridshell. The upper limit is assumed as fully stiff joints and serves for the strength calculation of the joints. The lower limit, used to determine the rotational stiffness, is iteratively determined between RFEM and IDEA Statics. This analysis is performed per individual type of connection detail. In addition, the model with weaker connections is used for testing and verifying the stiffness and stability of the gridshell (fig. 11). The underlying steel structure is also included Fig. 10 Overview of the RFEM structural model with different applied steel cross-sections

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Fig. 11 Overview of the RFEM structural model showing global deformations under one of the applied load-combinations (self-weight and snow)

as a support structure with respect to the force distribution. This was necessary because approaching the spring stiffness of the vertical supports would be an intensive iterative process as the stiffness would vary per load case. 6.3. Steel connections and glass analysis In principle, the dome has only one repetitive structural principle detail. Due to the free form geometry, however, every node is different and so many unique parts are needed. The final design for the Capital C resulted in approximately 1000 different steel elements and 200 different glass panes. Despite of this large number of unique parts, only two roof windows have been calculated. The standard size of 1630x1630mm1 for strength and stiffness under external loading, the smallest window (385x200mm1) under isochoric pressure. Analysis was performed using NX-Nastran, through FEMAP as pre- and post-processor. Validation was performed though a shadow calculation in the MEPLA software package. The following loads were included on the roof windows in accordance with NEN2608+C1:2014: Own weight glass, wind, snow, isochoric pressure, imposed maintenance load of 1.0kN/ m1 as well as 1.5kN. Because the roof windows can be walked on incidentally, one-sided lateral breakage in accordance with NEN2608 has also been taken into account. Finally, a fall test in accordance with NEN-EN 1991-1-1:2011 was carried out on the roof windows including PV cells.

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Composition of the roof glazing: Table 1: Composition glass Composition Type

Interlayer

6.6 / 18 / 6.6

Outer pane: Heat strengthened floatglass

Standard PVBfoil 0,76mm1

Inner pane: Heat strengthened floatglass

Standard PVBfoil 0,76mm1

Not all nodes were calculated. Only the nodes with the measuring loads from the main model were calculated with software IDEA Statica (fig. 12). The nodes to be checked were selected on: highest unity check in global model, highest moment My, Mz and MT direction, highest axial force as well as highest shear force Vy and Vz. Normative connections are taken both from model with stiff rotation stiffness as well as reduced rotation stiffness (Sj,ini / η). 7. File-to-factory The entire roof structure is file-to-factory produced applying the CNC production technique for the partial production of the tubular parts. The nodes of the dome are designed in such a way that they can be produced dimensionally using a tube laser. In the early stages of the engineering, two alternatives for the node connection were made and further developed into test productions. This allowed the validation of the technical detail and production method of the node through scale 1:1 production models. With this input, the software was further developed.

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The advantage of the proprietary parametric tool is that after changes to the line model, a complete Inventor model can be created quickly, in just four hours, which can be used for production. The model incorporates all facilities, such as holes for lighting, water-mist installation, glass fixing and acoustic panels. All the tubes are made file-to-factory and are prepared on the palette. All connections are digitized. The adjustable mould is a newly designed component. All complexity automatically comes out of the computer; the height, the position of the part and the degrees. The geometry of the model is extremely complicated because everything is skewed. The nail bed ensures that all complexity of the model can still be mounted in one go. 8. (Pre-)assemblage With regard to the steel connections of the dome, only one repetitive principle detail has been applied, as previously stated. In this project a system with welded frames from the factory and a bolted connection on site was chosen. The biggest challenge of this method to the chose pre-assembly method is to achieve the exact size of the welded assemblies. When you weld, you have to be able to estimate what the material is going to do due to thermal expansion and subsequent shrinkage of the steel. In order to ensure the correct dimensions of the steel structure, part of the structure has been pre-assembled. The test fitting of the most complex part of the dome, the ends, went well and verified the technical engineering and production method (fig. 13). In addition,

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Fig. 12 a) Engineering model and b) Structural analyses connection

Fig. 13 Test-assembly steel pre-assembled frames

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the size of the steel structure could already be experienced in the workshop. After the client and design team had inspected the test structure, the structure was disassembled and preserved by means of galvanization and powder coating. Because the frames are manufactured in the factory, they have a high dimensional stability, high-quality preservation and a high assembly speed on site. The assembly in the city centre of Amsterdam had to be done quickly, because the road could only be closed for two hours a day for hoisting the frames. Despite this restriction, the pre-fabrication of the frames to a high accuracy allowed the steel of the dome to be assembled in only eight days. 9. Conclusion The gridshell construction with the elegant lines of 'the new diamond' at the Diamond Exchange, could be developed within budget into a slim construction with minimalist details in steel and glass, thanks to the application of parametric tools developed by ZJA and Octatube. The computational design model for the spatial roof structure was generated to define the architectural design, analyse the geometry and topology, and at the same time provide tools for geometrical and structural optimization. This allowed for the current form of the roof structure to be realized, not only because it was technically feasible, but also cost efficient. This project therefore proves that parametric design and engineering is not only possible but will eventually save time and costs. The roof structure is an eye-catcher that draws one’s eye from afar to the Diamond Exchange and follows the lines based on the original design by Gerrit van Arkel. Anyone looking over the roofs of Amsterdam will easily see the transparent curves of the new roof structure from afar. Like a polished diamond, it sparkles in the light allowing the Diamond Exchange to shine again (fig. 14).

articles/news/11/6/16/1 (2007). Accessed 26 June 2007 Hamburger, C.: Quasimonotonicity, regularity and duality for nonlinear systems of partial differential equations. Ann. Mat. Pura Appl. 169, 321–354 (1995)

Paper originally published by Challenging Glass: https://doi.org/10.7480/cgc.7.4493

Discover more about Challenging Glass Conference here: www.challengingglass.com

Koos Fritzsche is a senior sales engineer at Octatube, a Netherlands-based Design and Build company specializing in bespoke building structures with an emphasis on advanced applications of glass and steel. With a background in structural engineering, he brings his technical knowledge to the table in the first phase of the project – often when the design is still in development. Collaborating with the architect, consultant or contractor, Koos uses parametric design tools as Grasshopper and Rhino to analyse variants and optimize the design. He specializes in complex geometries. Past projects he has worked on are: the C30 gridshell in the Hague, the Netherlands and Central Plaza in Dublin, Ireland. For the Capital C gridshell roof, Koos was involved as a sales engineer from the first sketches to the final construction. Wouter van der Sluis is a structural engineer at Goudstikker – de Vries, a Netherlands-based engineering company. Previously, he was employed at Design and Build company Octatube, where he started working attracted by the combination of design within a construction company. As a structural engineer at Octatube, he was involved in projects all over the world using advanced FEM skills from the start of a project till construction. Past glass projects Wouter worked on include an external full-glass elevator shaft at the Mauritshuis Museum in the Hague, the Netherlands and Innovationzentrum Spartherm in Melle, Germany where large cold bent glass units were used. For the Capital C gridshell roof he was involved as a structural engineer. Erik Smits is a project architect at ZJA, a Dutch architectural studio. Erik knew from an early age he wanted to be an architect, and shortly after graduating from TU Delft he joined ZJA. He enjoys the role of project architect and finds most gratification in organizing and managing the work process in such a way that it carries the architectural quality of the design until the final day of construction.

Jack Bakker is a parametric desiger at ZJA, a Dutch architectural studio. Initially Jack was schooled as a draughtsman and painter. Subsequently his love for mathematics inspired him to study computer science. At ZJA his knowledge and qualities could come together. Gradually he integrated his programming skills into the design process to produce engineering innovations in relation to light, energy, heat, water and geometry.

10. References Broy, M.: Software engineering — from auxiliary to key technologies. In: Broy, M., Denert, E. (eds.) Software Pioneers, pp. 10–13. Springer, Heidelberg (2002) Cartwright, J.: Big stars have weather too. IOP Publishing PhysicsWeb. http://physicsweb.org/ 124

Sajti, C.L., Georgio, S., Khodorkovsky, V., Marine, W.: New nanohybrid materials for biophotonics. Appl. Phys. A (2007). doi:10.1007/s00339-0074137-z

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Daniel Inocente, Georgi Petrov, Christoph Timm

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Introduction The international space community is continuously working on new ideas to sustain human exploration goals on the surface of the Moon and beyond. In one recent study on the future of space habitats, the European Space Agency (ESA) partnered with design, engineering, and urban planning firm Skidmore, Owings & Merrill (SOM) to bring multiple sectors together to investigate the possibilities of space architecture. The research offered insights into the technical and architectural constraints of building on the Moon, and to realizing humanity's long-term exploration goals in space. In the partnership between SOM and ESA, the Moon Village concept served as the foundation to take a deeper look into the design and engineering limits of deployable habitats. Habitat Design The primary habitat module is designed to be manufactured, tested, and launched from Earth with a significant amount of its internal equipment pre-integrated for use. It utilizes a hybrid structural system composed of rigid and flexible elements, and includes several deployable systems, such as an exterior shell, a floor system, and multi-purpose racks that could be configured and secured in a stowed condition during launch. Once on the surface, the habitat would be transferred to the building site already prepared for deployment. When it’s pressurized, a team on Earth could conduct remote testing of the internal equipment for nominal performance. At this point, the crew arrives, performs any pending deployment activities, and occupies the habitat. The interior is designed to remain flexible so that a wide range of mission scenarios can be accommodated. The habitat addresses functional, environmental, and performance constraints, while also emphasizing human-centered design principles – all of which are characterized in numerous architectural features. A single unit offers a net habitable volume of up to 390 m3 and a net habitable area of up to 104 m2. To maximize the functionality of central spaces, the vertical structure is placed at the perimeter and integrated with windows and secondary mechanical distribution systems. The primary mechanical systems are located within the composite floor assembly, with payload rack units mounted near the center in a stowed configuration; during occupancy, it is displaced 126

to the perimeter walls. The environmental protection system includes a multi-layer assembly with structural mesh directly woven into the mega-columns to increase resistance under tension. This structural mesh supports the internal pressure loads, and the windows along the rigid elements provide visual connectivity and situational awareness for occupants. Although it is an engineering challenge to integrate windows into the envelope, they are essential to the experience of living on the Moon, and to the psychological wellbeing of the crew. Space Station The International Space Station (ISS) has been the longest operating space station currently

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occupied in orbit. One of the most iconic elements of the ISS is the largest glass window ever flown in space. The Cupola, which is attached to the Tranquility module, technically known as Node-3, was added to the ISS in 2010. The European-built window assembly is now an integral part of the ISS and provides astronauts with an incredible view of Earth in what would otherwise be a small space filled with equipment and tools. The window on the ISS was originally added to serve as an observation and working node operating the station's robotic arms, and to take high resolution photographs of the planet below. Today, it maintains its view of Earth while the ISS orbits the planet at 27,580 kilometers per hour, 400 km away.

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European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, enjoys the view of Earth from the windows in the Cupola of the International Space Station. Image Credit: NASA

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SOM and ESA Habitat Concept Image Credit: © SOM | Slashcube SOM and ESA Habitat Concept Image Credit: © SOM | Slashcube GmbH

The windows on the ISS have to withstand the intense constraints of the space environment and the mass limitations of transportation into orbit. They have to simultaneously endure exposure to extreme temperatures, micro meteoroids and orbital debris (MMOD) traveling at high velocities, all while containing the internal atmospheric pressure. 128

The pressure differentials between the vacuum of space and the human-sustaining habitation likewise had to be considered across all structural elements. Integrating openings into the structure is a complex endeavor, and requires innovative engineering solutions. When introducing windows and glass, it is essential to include structural redundancies,

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GmbH but this also increases the mass. The Cupola was pre-assembled and integrated into Node-3 before being launched with the space shuttle and attached to the ISS. This real-world precedent for a window in space demonstrates the challenges of integrating glass into orbiting habitats. Designing for surface structures on other planetary surfaces, however, requires an entirely new way of designing and engineering. Together with ESA, SOM investigated how windows could play an important role in the design of an entirely new type of habitat. Lunar Challenges When discussing the design of a human habitat for such an extreme environment, it is important to describe the challenges that must be confronted. The first challenge on the Moon that comes to mind for most people is the decrease in gravity intelligent glass solutions | summer 2021

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relative to that of Earth’s surface. The Moon is smaller and has a lower overall density than Earth – resulting in a surface gravity that is only 16.5% the strength of Earth’s. Ironically, this does not make construction easier. The loads on any human habitat generated from the difference in pressure between the interior and exterior are about an order of magnitude greater than the weight of the materials necessary to enclose the space. Thus, the major structural problem on the Moon is holding the building together given the pressure loads, and by not holding them up against Earth’s gravity. The second primary challenge is the lack of atmosphere. With no air in space, the mechanical systems must supply oxygen 130

and recycle carbon dioxide in a closed loop. Additionally, without a thick atmosphere to insulate the moon’s surface, the diurnal temperature variation is also much larger – making temperature-induced stresses a significant problem for the structure and the insulation. The Moon’s weak magnetic field, combined with the absence of atmosphere, means that the lunar surface has virtually no protection from cosmic radiation. There are three different types of radiation to worry about. First, there is the solar wind, a stream of charged particles that is constantly emitted from the sun. The second is cosmic rays, which are produced by exploding stars in the galaxy. One way settlers

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on the Moon can be shielded from these first two types of radiation is by covering all habitable spaces with lunar regolith, a powdery material that covers the entire surface of the Moon, or by using advanced materials. The third source of danger is solar flares, which form when the sun expels large clouds of charged particles. The large radiation emissions of solar flares require a much more substantial shielding. Fortunately, humanity has a fleet of spacecraft that monitor the sun and can provide up to one hour of advanced warning before the flare reaches the Moon. The habitat can therefore include a solar storm shelter accommodating all settlers for the duration of a solar flare. The final set of challenges are presented by the Moon’s great distance from Earth, and the astronomical cost of delivering so much mass 132

to the surface of the Moon. Every system has to be designed to an extreme level of robustness and be easy to maintain. Window Design The windows on the habitat are integrated into the metallic structural columns. Each measure approximately 200 cm in height and 80 cm in width. Altogether, the 12 windows represent a total area of 10.5 m2 and a mass of approximately 1,640 kg. Their vertical orientation fits within the boundary of the rigid metal frame, but still provides a large viewing area. Each window is built using advanced technologies to defend the sensitive, fused silica glass panes from years of exposure to solar radiation and debris impacts. To minimize exposure, solid metal shutters can be deployed on the outside to protect the glass assembly. During the crew's resting hours, when no transparency is desired, the shutters can cover

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the windows and later open during waking hours. Furthermore, light ingress into the module can be controlled with interior sliding shutters, which operate much like the shutters on commercial airplane windows. This practical interior feature is particularly important for the habitats that are closest to the lunar polar sites, where low sun angles are prevalent most of the day and can create glare on the inside. The windows on the lunar habitat specifically provide the astronauts with a visual connection to their environment. Each window maximizes views out of the different levels of the habitat, while keeping the glass dimensions as minimal as possible. Naturally, the geometry of the windows needs to be articulated in a way that works with the form of the capsule. Unlike windows on Earth, the windows for this space habitat are not primarily designed to illuminate the interior and have no ventilation

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All the glass substrates are borosilicate glass, which has a very high thermal resistance and is used extensively in environments with high temperature swings. Its thermal coefficient of expansion is about one-third of that of regular soda lime silica float glass, which is used for most construction projects on Earth. In addition, borosilicate glass has the

advantages of increased hardness, strength, and durability, all while being lighter. These characteristics are especially desirable in space architecture, and can help us create a lunar habitat that is not only designed for survival, but also for wellness – a true home in an environment where we have never lived before.

Georgi Petrov is practicing architect and structural engineer. He is an Associate Director in the structures group at the New York office of Skidmore, Owings & Merrill, where he works on highrises, long span roofs, and specialty glass and steel structures in North America, Asia and the Middle East. He is a leader in pioneering SOM’s involvement into design for structures in outer space and in developing novel project delivery methods in close collaboration with fabricators. He is a both licensed Architect and Professional Engineer and an adjunct professor at NYU's Tandon School of Engineering. Christoph Timm is the Senior Leader of the Enclosure Group at SOM — a practice embedded among the design and engineering studios in the firm’s New York office. With two decades of experience in the creative field, Christoph has designed a wide variety of projects encompassing products, furniture, street lights, and architecture. Christoph s expertise is in both high-performance building enclosures and in their aesthetically crafted appearance in varying light conditions. Efficiency and innovation are among the many considerations central to his design process. At SOM, Chr istoph started a construction site visit program that regularly takes young architects to different sites in New York to create a better understanding of the complexities of construction in relation to design. Outside of SOM, Chr istoph shares his expertise actively at conferences and industry events, and has lectured on design and building performance-related topics. He al so sits on scientific advisory committees for a variety of conferences.

functionality at all. Whereas glass windows on Earth are typically engineered for expected wind loads, the Moon poses an incredible atmospheric pressure differential between the interior and exterior. This drives the structural glass design. Window sizes are limited by substrate thicknesses for safety and restrictions in weight. For serviceability, the outer and inner sacrificial pane of the multi-layered glass assembly can be replaced if there are any breaks or scratches.

As a Senior Designer based in New York, Daniel Inocente works on both U.S. and international projects small and large, each with its own unique circumstances and opportunities. He emphasizes the human experience and design innovation by leveraging building science, design technologies, and interdisciplinary expertise. He has worked on mixed-use, residential, commercial, transportation, aviation, government, cultural, science, education, and space projects throughout his career. At SOM, Daniel has worked on multiple tall buildings, including the Hangzhou Tower, Guiyang World Trade Center, Zhongtian Tower, Zhuhai S3 Tower, and Tour Charenton. Lucas Blair Simpson Daniel is also a member of a dedicated team based in New York that © SOM specializes in digital technology, and utilizes this expertise to collaborate on multiple projects across the world, conduct research, and develop design ideas. He has also had the opportunity to establish and lead interdisciplinary partnerships with the space sector, bringing in partners such as ESA, NASA, MIT, and private companies. These initiatives reflect his passion for space architecture and the important role that he believes we have in contributing to future thinking about humanity's progress through social, technological, and cooperative endeavors.

The reference used for the window glass design on the Moon Village habitat is the 4-pane assembly of the Cupola on the ISS. Like the Cupola, the idea includes a multi-layered window system composed of the following elements: 11.4 mm debris pane, 2 x 25 mm pressure pane, and an inner 9.3 mm scratch panel, which together results in 155.7 kg/m2 for the glass assemblies. intelligent glass solutions | summer 2021

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Dr. Hosse “The AEC industry is no exception to this tsunami of change. We are not only changing the manner in which we work…but also are questioning the merits of some of our design and material selection processes by introducing circularity into our work and by squeezing waste and carbon out of them”

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A true visionary, in his own words

IGS Interviews

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In this Edition of ‘The Glass Word”, IGS Magazine’s Lewis Wilson talks candidly with Dr Hossein Rezai, the first and only engineer to receive the coveted title of “Designer of the Year” from the President of Singapore. He is the Founding Principal and Director of design engineering consultancy Web Structures; an international multi-disciplinary firm with a unique ‘fusion Engineering ‘approach, blurring the traditional separation between architectural design aesthetics and structures. His latest venture as the inaugural Global Design Director in Ramboll has the ambition to scale the pioneering design-oriented engineering ethos that he developed in Web Structures into Ramboll to help steer the company towards Purposeful Design and Environmental Congruency. We delve into his thoughts on collaboration, leveraging digital technologies and glass as a building material both now, and in time still to come.

Lewis: Your company WEB STRUCTURES is a pioneer in ‘fusion engineering’. Can you outline the fundamental ideas behind this concept and discuss how this approach contributes to the final architectural product? Hossein: Flawed and out of date perception of a linear and over-simplified understanding of the Quality spectrum, tends to place cost efficiency and design richness at the two opposing ends. There is this outdated perception that objects and buildings that we design are either cheap or good; that they can’t be both. At the quality end you “leave your wallet” with the designer who spends freely to get you a good design. In contract at the cheap end, you inevitably get things which are aesthetically poor, non-responsive, or both. “fusion engineering”, a term we coined a few years ago, challenges this simplistic perception, and in fact shows that high quality and high cost do not have to come together. One can indeed have quality at a lower cost through the value of design. fusion engineering is the circular quality wheel, if you like ... in our work over the past 25 years or so we have demonstrated this numerically on many occasions for different scale and genre of projects. We have shown how highly bespoke design leads to economy. And how, in contrast, “standardisation” is always analogous with waste, higher cost and larger carbon footprint.

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Lewis: The work of Web Structures requires substantial collaboration with architects, designers, engineers and consultants. As a firm, how challenging is it to extract the best from all the parties involved, while still holding on to your own ideologies and design intent? Hossein: Our ideologies are in our areas of core competence. Our creative energy draws on this core competence to innovate in the areas where we overlap with other competencies. Collaborative innovation happens when practitioners from different core competencies learn and speak the common language of design. Beautiful things happen in the areas where engineers overlap with architects and other designers. We all 138

need to be “bi-lingual”; engineers must be able to recite the most amazing poetry in engineering, yet be able to communicate same in the language of design so that others appreciate the romance and articulation of their contribution. Likewise, architects and others must be able to communicate in the common language of design. Or no meaningful conversation and interaction will happen, and everyone will feel frustrated, not understood, nor appreciated, leading to input from each discipline piled up on top of each other rather than being integrated into one congruent whole. Lewis: Collaboration is not limited to human beings; digital technology has become a fundamental design partner.

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What are the benefits of collaborating with and leveraging digital technologies from the design phase through to the completion of a building? Hossein: Value of collaboration has been undeniable in the ascent of our species to where we are as the undisputed leading species on top of the food chain. It is primarily by collaborating with one another that we have carved this position for ourselves. The key to our apparent success has been the fact that we collaborate not only with people and colleagues we know, but with those we do not even know exist. The test is when you open up any of the gadgets we own. Once the cover is removed you see myriad of components each of which is manufactured by different people and factories from across the

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globe. The individual workers or companies whose products feature in the whole system would probably not know where their components would end up and next to whose components. But they sure are “collaborating” with one another. The relationship we are formulating with machines now is a key determinant in our progress into the future. Machines are empowering us not only to do the things that we have always done better, but also to do things we were not able to do only a few short years ago. I would go further to say that through augmentation with modern machines we have been emancipated to think and imagine designs that we would be inhibited to imagine a few years ago. Machines have broadened our horizons. And THAT is the future … intelligent glass solutions | summer 2021

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Lewis: There are undoubtedly numerous advantages to the digital revolution From BIM to Artificial Intelligence and BIG Data, we can now design more complex, efficient and responsive buildings. But do you think anything has been lost because of it? Hossein: The process of technology development and adoption is not binary. We should not see progress as “gain of new, but loss of old”. I do not look at the journey in a sentimental and nostalgic way. We are on a journey in which we learn from the past and move into the future. The whole of the past is in the whole of the future. Nothing is really ever lost. For those who are fearful of the advent of digital technology and the role that machines will play in our future, they need to ask themselves 3 simple questions: who am i? where do I come from? What’s my ethos? Those of us who can have meaningful answers to these questions will never be replaced by machines, because no machine in the foreseeable future will be genuinely able to answer these 3

questions. I recall the newspaper headlines when Watson (IBM’s artificially intelligent machine) beat the chess world champion a few years ago. In amongst the jubilation of the programmers and machinists who made and operated Watson, the headlines read “Watson does not know he has won!”. And this is the difference between us and the machines. This is a super long way of answering your question. I could just have said “NO”. haha … Lewis: This may sound silly but we live in a funny old world; In a dystopian future ruled by machines, can you see the day when artificially intelligent automated technology can conceptualize, design, engineer and build a project, making the job of architects and structural engineers obsolete? Hossein: “There’s no such things as silly questions. Only silly answers.” I not only can see that day, but am actually looking forward to it! Everything that any of us are doing right now can technically be done by a machine. We are already effectively and technically obsolete. That’s why we need to reinvent ourselves and move onto the next curve rather than live in the fear that machines are going to take over and leave nothing for us to do. Can you imagine if a leader in an organization thought like that about his/her up and coming staff?! And saw them as threats rather than opportunities to relinquish more and more of what he/she is doing to others to be empowered to learn and do other things. Lewis: WEB STRUCTURES is renowned for its “out-of-the-box” concepts, innovative thinking and structured creativity. How do you maintain your creativity and continue innovating in an architectural climate where many projects reproduce existing tried and tested ideas? Hossein: It is not easy, especially when there is the pressure of short-term financial performance. I know a lot of other people and practitioners who are on the same trajectory. They will tell you also that it is not easy. You see, creativity is hard work, it is an attitude. It is an intent that one decides to explore new paths and ideas rather than fall back on the previously done and tried and tested solutions and answers. It gives one a sense of constant

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anxiety. But the creative anxiety is good anxiety. The test is in fact to be in touch with one’s inner feeling and listen to yourself. Are you anxious? Are you in doubt if the idea you are exploring may or may not work? If yes, then you are in a creative space. You are in a new space. Where you have not been before. If not, then you are regurgitating something from the past. You may be doing this inadvertently and subconsciously. If you have no doubt, then you are not in a creative space. I feel very 142

uncomfortable when I am totally comfortable! That’s my secret. I suppose everyone has his/her own litmus test. Lewis: COVID-19 has, to say the least, been highly disruptive to the world and AEC industry in 2020/21. In your view, what effects has the pandemic had on design thinking? Has it affected structural engineering and your key considerations in the design phase of a project?

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Hossein: The pandemic, like other events in our recent history, has accelerated the rate of change which we were undergoing before the pandemic. It has really not changed the path or the trajectory our industry has been on. We have been asking ourselves questions on the validity of our processes, our practices and our relationship with our work and with the natural environment. Our industry thinkers have been raising issues of climate change, social and inter-species equity, carbon footprint,

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etc etc for many decades now. Environmental sustainability, the things that we build, materials we use, the way our cities operate and the like have been questions we have been asking ourselves constantly over many years. This pandemic has made more of us ask these questions and take these questions and possible answers to them more seriously, as the virus has left its indelible mark in our lives and livelihoods. The upshot of all these frictions between the built environment and the natural environment is that we must change. The mantra of “Business-as-usual is not sustainable” is now a clear reality for most of us. The AEC industry is no exception to this tsunami of change. We are not only changing the manner in which we work, with work from home and more remote collaboration, but also are questioning the merits of some of our design and material selection processes by introducing circularity into our work and by squeezing waste and carbon out of them.

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Lewis: Over the past decade we have seen a heightened sense of urgency surrounding climate change and sustainability in architecture. Do you believe glass has a place in the sustainable, energy efficient, highperformance buildings of the future? Hossein: Glass definitely has a very important role to play in the future of our built environment. Structural properties of glass have always fascinated me. Recent advances in glass technology leading to more resilience and redundancy in these properties are encouraging. Integration of technology into glass as a material and in the process of making glass have also enhanced environmental properties of the material with better heat and light insulation. What I would like to see happening moving forward is glass that can breathe; one that can allow air movement and natural ventilation while providing protection against water ingress. Not sure how far we are from achieving this, but I sure look forward to that.

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Lewis: And finally, can you introduce us to some of the projects that you are currently working on, and perhaps give us a heads up on some projects in the pipeline that look set to gain traction and change the game in 2021 and beyond? Hossein: We have two expo pavilions about to be completed in Dubai for the upcoming expo, one for Singapore with WOHA architects and the other for Malaysia with Hijjas architects. I am very excited to see the finished work soon. In Singapore we are doing a stadium in downtown by the marina, a competition winning scheme with WOHA architects, partly in land and partly on water. Another competition winning scheme we are working on in Singapore is the new science center which we won with Zaha Hadid architects and Architects 61. Over in Kuala Lumpur we are building a mixed development near the Petronas Towers. The development has

Dr. Hossein Rezai Dr. Rezai is an engineer, a design visionary and an educator. One of the initiators of the concept of “fusion engineering”, he is the first and only engineer to receive the coveted title of “Designer of the Year” from the President of Singapore. He is very passionate about the process of advanced computational design, and a holistic approach to architecture + structure + environment, and circularity in the construction process. Dr Rezai’s highprofile contributions to industry discourse include his involvement on the 13th cycle of Aga Khan Award for Architecture’s Master Jury in 2016, as a jury member for the Singapore President’s Design Award (2017 - 2018) and as Vice Chair (2019-2020). Dr Rezai is the Global Design Director of Ramboll and founding Director of Web Structures and Web Earth. His latest initiative, on Advanced Computational Design aims to redefine the collaborative nature of designers working with machines to overcome the compound challenges faced by the building industries, and the environments within which they are deployed. Dr. Rezai lectures extensively, and has covered ongoing crit and consultation in various architectural schools including those at the National University of Singapore (NUS), the Singapore Univiersity of technology

3 towers; one at 72 storeys and a twin towers at around 62 and 58 storeys. The interesting thing about the twin towers is that they twist away from one another as they go up; this creates a beautiful dynamic form which makes the development pretty bespoke. The reason the towers twist as they go up is to avoid a situation where the residents of one tower overlook into those in the other tower. It is a highly purposeful twist which adds to the quality and value of the design and the property. We are doing quite a few other projects in around 15 countries as we speak. They all are unique, and I can tell you a lot about them: like a university in Dhaka and one in Singapore, both with WOHA, a highprofile development off the coast of Penang in Malaysia with the team from BIG out of New York, a breathtaking residential tower with RSHP in Taipei and a, as yet, confidential shop somewhere in the world with Foster and Partners.

and Design, Politecnico Di Milano and more recently at the University of Southern Califonia. His research and academic career goes all the way back to when he was a research fellow at the University of Westminster. He conducted a number of research initiatives and supervised projects including a PhD on punching shear reinforcement in flat slabs. This work led to various publications in international magazines including the Structural Engineer and the American Concrete Institute. His academic career continues today with involvement with the National University of Singapore (NUS) and more recently the Singapore University of Technology and Design. Dr. Rezai was awarded a Ph.D in 1985 for his work on reinforced and prestressed concrete structures. He further pursued his research interests on a post-doctorate research programme on the assessment and upgrading of existing structures before joining the industry in January 1987. He has been involved with the design and development of a number of fairly high profile structures in the UK, South East Asia and elsewhere across the globe. Dr Rezai is a proponent of highrise and dense urban development, with emphasis on innovative structural systems for tall, supertall and mega tall buildings.

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AUTHORS DETAILS SUMMER 2020

JAMES CARPENTER James Carpenter Design Associates Founder 145 Hudson St # 402, New York, NY 10013, USA info@jcdainc.com + 1 212 431 4318 www.jcdainc.com DR. ALICIA DURÁN International Commission on Glass and CSIC President and Research Professor Instituto de Cerámica y Vidrio – CSIC Kelsen 5 28049, Madrid, SPAIN aduran@icv.csic.es (0034) 917 355 840 www.glass.icv.csic.es CARRIE RUDDICK Princeton University of Architecture Communications Manager Princeton University School of Architecture S-110 Architecture Building Princeton, NJ 08544, USA carrie.ruddick@princeton.edu (609) 258-0991 www.soa.princeton.edu

KLAUS REUSCHLE Josef Gartner GmbH Project Director Gartnerstraße 20, 89423 Gundelfingen an der Donau, Germany gartner@permasteelisagroup.com +49 9073 840 www.josef-gartner. permasteelisagroup.com

KATHERINE CHAN AND LAURA KARNATH Walter P Moore Senior Associate and Senior Enclosure Technical Designer 1301 McKinney St #1100, Houston, TX 77010, United States info@walterpmoore.com +1 713-630-7300 www.walterpmoore.com

ROBERT MATTHEW NOBLETT Behnisch Architekten Partner Behnisch Architekten Rotebühlstraße 163A 70197 Stuttgart Germany pr@behnisch.com +49 711 60772–0 www.behnisch.com

VALÉRIE HAYEZ Dow Global Façade Engineering & Architectural Design Engineer Bachtobelstrasse 3, 8810 Horgen, Switzerland +41 44 728 21 11 www.dow.com

ROMAN SCHIEBER Knippers Helbig Associate Director Knippers Helbig GmbH Tübinger Str. 12-16 70178 Stuttgart Deutschland stuttgart@knippershelbig.com +49 711 248 39 360 www.knippershelbig.com

NEIL DOBBS Multiplex Head of Facades Multiplex Construction Europe Ltd 99 Bishopsgate, 2nd Floor, London, EC2M 3XD, United Kingdom +44 20 3829 2500 www.multiplex.global

LUKE FOX Foster + Partners Senior Executive Partner and Head of Studio Riverside, 22 Hester Road, London, SW11 4AN, United Kingdom london@fosterandpartners.com +44 20 7738 0455 www.fosterandpartners.com

DR. KAYLA NATIVIDAD Pilkington North America Architectural Technical Service Engineer Pilkington North America 811 Madison Avenue, Toledo, OH 43604-5684, USA thomas.o’day@nsg.com +1 419 467-7245 www.pilkington.com

MASSIMILIANO FANZAGA Permasteelisa Communication Manager Viale E. Mattei 21/23 | 31029 Vittorio Veneto, Treviso, Italy m.fanzaga@permasteelisagroup. com +39 0438 505504 www.permasteelisagroup.com

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DR MATYAS GUTAI Water-filled Glass Ltd and Loughborough University Founder and Lecturer in Architecture Epinal Way, Loughborough LE11 3TU, UK M.Gutai@lboro.ac.uk +44 (0)1509228023 www.waterfilledglass.com KOOS FRITZSCHE Octatube Senior Sales Engineer Rotterdamseweg 200 2628 AS Delft Nederland info@octatube.nl +31 (0)15-7890000 www.octatube.nl WOUTER VAN DER SLUIS Goudstikker De Vries Structural Engineer Rentmeesterstraat 50 1315 JS Almere almere@goudstikker.nl 088–6780 300 www.goudstikker.nl

ERIK SMITS AND JACK BAKKER ZJA Project Architect and Parametric Designer Pedro de Medinalaan 7 NL-1086 XK, Amsterdam Netherlands info@zja.nl 020 5352200 www.zja.nl GEORGI PETROV, CHRISTOPH TIMM AND DANIEL INOCENTE Skidmore, Owings & Merrill Associate Director, Senior Leader and Senior Designer 7 World Trade Center 250 Greenwich Street New York, NY 10007 +1 212 298 9300 www.som.com ANDREAS BITTIS Saint-Gobain International Marketing Manager SAINT-GOBAIN Les Miroirs 18, avenue d’Alsace 92400 Courbevoie FRANCE +33 1 47 62 30 00 www.saint-gobain.com DR. HOSSEIN REZAI Web Structures Founding Principal and Director 40 Carpenter Street, Singapore 059919 webstruc@webstruc.net (65) 6223 9208 www.webstruc.net

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30 HUDSON YARDS ARCHITECT: KOHN PEDERSEN FOX ASSOCIATES BALUSTRADE: CS FACADE

GLASS BONDING IS OUR PASSION GLASS GROUTING OF BALUSTRADES Sika offers solutions for the challenging modern architecture. The gigantic elements of the glass balustrade of the Observation Desk at 30 Hudson Yards have been safely and durably fixed with the self-levelling polyurethane glass grout SikaForce® GG. A perfect example for highest architectural freedom of design. Contact us now. Sika Services AG FFI Facade · Fenestration · Insulating Glass Tueffenwies 16 · CH-8048 Zurich · Switzerland Tel. +41 (0)58 436 40 40 · Fax +41 (0)58 436 55 30 www.sika.com/facade