Hex Mod - Diploma Project (University of Cyprus - Department of Architecture)

a prototype for modular structures, prefabrication and lightweight construction in the design of tall buildings

Δρ. Μάριος Φωκάς, Αναπληρωτής Καθηγητής Τμήμα Αρχιτεκτονικής, Πανεπιστήμιο Κύπρου 1ος Επιβλέπων Δρ. Ανδρέας Σαββίδης, Επίκουρος Καθηγητής Τμήμα Αρχιτεκτονικής, Πανεπιστήμιο Κύπρου 2ος Επιβλέπων Δρ. Ιωάννης Μπαλάφας, Ειδικός Επιστήμονας Τμήμα Πολιτικών Μηχανικών και Μηχανικών Περιβάλλοντος, Πανεπιστήμιο Κύπρου 3ος Επιβλέπων

ΚΥΡΙΩΣ ΕΠΙΒΛΕΠΩΝ ΚΑΘΗΓΗΤΗΣ Δρ. Μάριος Φωκάς, Αναπληρωτής Καθηγητής Τμήμα Αρχιτεκτονικής, Πανεπιστήμιο Κύπρου

Υπογραφή

............................................................................

supervising committee

hexmod

ΕΠΙΒΛΕΠΟΝΤΕΣ ΚΑΘΗΓΗΤΕΣ ΔΙΠΛΩΜΑΤΙΚΗΣ ΕΡΓΑΣΙΑΣ

01

I would like to thank the academic and administrative staff at the Department of Architecture at the University of Cyprus for their continuous pursuit to improve the quality of our academic careers, and for their investment in both our future and the future of the Department.

I would like to thank my supervisor, teacher, and friend, Dr. Marios Phocas, for his unfailing faith in my strengths and qualities. His focus and clarity of thought have proven an inspiration to rise above the challenges faced during my time at the university.

I would also equally like to thank my teacher, friend, and mentor, Dr. Christakis Hadjichristou, for initiating my mind to the world of Architecture, for his enthusiasm and creativity, for his appreciation of my work and personality, and for his repetitive display of trust.

Many thanks also go to my teachers Dr. Panayiota Pyla, Dr. Andreas Savvides, Dr. Socrates Stratis, Dr. Aimilios Michael, Dr. Odysseas Kontovourkis and all the adjunct academic faculty of the

Moreover, I am very thankful for the support of Dr. Yiannis Balafas, for believing in, encouraging and supporting me with his consult and advice during my studies.

I would similarly like to express my gratitude to Dr. Anastasia Pexlivanidou-Liakata and her assistant Lecturer Leda Machia, for the best semester of my academic life, full of passion and emotion.

Finally, I express my thanks to all my classmates, for the memories we share together, and for memories to come.

Most of all, I am eternally grateful to my family and close friends, for their support, their faith, their struggles, their challenges, their help and patience, in order for me to make it through.

acknowledgements

Department for sculpting me in the best possible way over the course of the past five years.

02

introduction

abstract

page 04

flexible theoretical concepts

page 05

flexible conceptual proposals

page 08

structural demands in tall buildings

page 10

comparison of structural systems

page 11

materialized examples

page 12

design of structure

page 14

unit morphology

page 19

construction details

page 20

elevation

page 21

visualizations

page 22

plan variations per floor / interior visualizations

page 24

appendix

presentation layouts

page 26

bibliography

bibliographical and web resources

page 34

table of contents

main analysis

03

01

introduction

introduction is a project that explores the morphology and feasibility of applying flexible

structures in tall buildings, on a functional and constructional level, based on modularity and

Το

hexmod

είναι μια μελέτη που εξερευνά την μορφολογία και την δυνατότητα

εφαρμογής ευέλικτων δομών στα ψηλά κτίρια, σε λειτουργικό και κατασκευαστικό επίπεδο, βασισμένη

prefabrication, giving a greater level of customization to the built form from a more performative

στην προκατασκευή και την τυποποίηση, δίνοντας ένα μεγαλύτερο επίπεδο παραμετροποίησης στην

perspective.

δομημένη μορφή από μια προοπτική που εστιάζεται στην αποδοτικότητα.

Following an analysis of flexible theoretical concepts of the past, such as the Spatial City by Yona

Ακολουθώντας μια ανάλυση ευέλικτων θεωρητικών προτάσεων του παρελθόντος, όπως το Spatial

Friedman, the Plug-in City by Archigram, Gunther Domenig’s Uberbaung Ragnitz, and the Nakagin

City του Yona Friedman, Plug-in City από τους Archigram, το Uberbaung Ragnitz του Gunther

Capsule Tower by the metabolist Kisho Kurokawa, the approach was divided into a two-fold scenario:

Domenig, το Nakagin Capsule tower του μεταβολιστή Kisho Kurokawa, η προσέγγιση διαχωρίστηκε σε

the development of a main infrastructure that services a number of structurally and functionally

ένα διττό σενάριο: μια κύριας υποδομή που υποστηρίζει ένα αριθμό στατικά και λειτουργικά αυτόνομων

autonomous units that are assembled together to create one unified building. Upon reviewing a

μονάδων που συνδέονται μεταξύ τους και στην ενότητα τους δημιουργούν ένα ενιαίο κτίριο.

number of contemporary conceptual proposals on the same subject, it was deduced that the

Μελετώντας σύγχρονα παραδείγματα προτάσεων για το συγκεκριμένο θέμα, απορρέει ότι οι σχέσεις

relationships that governs the evolution of tall structures can be organized in 3 different hierarchies of

που κυβερνούν την κατασκευή και εξέλιση των ψηλών κτιρίων μπορούν να οργανωθούν σε 3

development: monolithic structural cores with add-on modular units, structurally independent

διαφορετικές ιεραρχίες ανάπτυξης: μονολιθικοί δομικοί πυρήνες με προσθετικές τυποποιημένες

stackable modules, and modular structural infrastructure. Evidently, it was chosen that the project

μονάδες, δομικά ανεξάρτητα στοιβαζόμενες μονάδες, και τυποποιημένη στατική υποδομή. Η εργασία

would try to combine these positions in order to create a structurally efficient and prefabricated

επιχειρεί να τις συνδυάσει με σκοπό να δημιουργήσει μια δομικά αποδοτική και προκατασκευασμένη

method of construction for use in the design of tall buildings.

μέθοδο δόμησης για χρήση στο σχεδιασμό ψηλών κτιρίων.

As the structural necessities needed to be established from the start, it was decided that the

Έχοντας υπόψη ότι οι στατικές προδιαγραφές έπρεπε να ληφθούν υπόψη από την αρχή,

prosthetic modules would come in a variety of uses – residential spaces, office spaces, outdoor

αποφασίστηκες ότι οι προσθετικές μονάδες θα ανταποκρίνονταν σε ένα σύνολο χρήσεων:

vegetation and public spaces. Moreover, it was chosen that in order to have a more efficient

κατοικίες, γραφεία, υπαίθρια βλάστηση και δημόσιοι χώροι. Επιπλέον, για να υπάρχει πιο

response to lateral wind loads, the plan view of the building should be circular in shape, in order

αποδοτική και ομοιόμορφη αντίδραση του κτιρίου στα κάθετα φορτία ανέμου, η κάτοψη του

distribute the forces acting on it more evenly. Upon comparison of the structural systems applicable in

κτιρίου θα έπρεπε να έχει κυκλική μορφή. Μετά από την σύγκριση δομικών συστημάτων που

the design of high-rise developments for interior and exterior structures, it was selected to base the prototype on an outrigger interior, but applying a honeycomb-like structure on the exterior, that would serve a dual purpose: to act as the tension-bearing structure bracing the outrigger trusses together, but also to act as a support for the external modules to attach on the main infrastructural building. The structural systems were chosen based on their structural effectiveness and efficiency, limitations in floor planning, weight and cost of construction.

The morphology of the honeycomb structure on the exterior was generated based on a number of factors. The first and foremost set of factors on the selection process was architectural. The search for

χρησιμοποιούνται στην ανέγερση ψηλών κτιρίων, προτιμήθηκε να βασίσουμε το πρωτότυπο σε εσωτερικό outrigger, με κυψελοειδές εξωσκελετό με διπλή χρησιμότητα: ως εφελκυόμενη δομή που συγκρατεί τα χωροδικτυώματα outrigger μεταξύ τους, καθώς και ως στήριξη για τις προσθετικές μονάδες. Τα δομικά συστήματα επιλέχθηκαν με βάση της στατικής τους αποτελεσματικότητα και αποδοτικότητα, περιορισμούς στο σχεδιασμό, ιδιοβάρος και κόστος κατασκευής. Η κυψελοειδής μορφολογία του εξωσκελετού βασίστηκε πάνω σε ένα αριθμό παραμέτρων, η κυριότερη

των

οποίων

ήταν

αρχιτεκτονική.

Η

αναζήτηση

μιας

μορφολογίας που

θα

a morphology that would optimize a number of architectural factors, such as day lighting, natural

βελτιστοποιούσε ένα αριθμό αρχιτεκτονικών απαιτήσεων, όπως φυσικός φωτισμός και

ventilation, less space consuming connection of independent modules and stronger cross bracing

εξαερισμός, εξοικονόμηση χώρου κατά την σύνδεση και πιο ανθεκτικό δομικό σύστημα

structure (leading to more efficient use of structural material and hence achieve a more light-weight

(οδηγώντας σε πιο αποδοτική χρήση δομικών υλικών και έτσι χαμηλότερο ιδιοβάρος κατασκευής).

design). By using a hexagonal form, it was possible to pack the plug-in modules more densely, hence

Χρησιμοποιώντας εξαγωνοειδή μορφή, ήταν δυνατό να αυξηθεί η πυκνότητα τοποθέτησης

making it possible to pack a larger number within the same volume. The length of the modules is

μονάδων μέσα στον ίδιο όγκο. Το μήκος των μονάδων κυμαίνεται μεταξύ 8 και 12 μ σε μήκος, και

variable between 8m and 12m in length, and it is possible to house up to 16 units per floor, residing on

είναι δυνατό να τοποθετηθούν μέχρι και 16 οικιστικές μονάδες ανά όροφο σε πύργο διαμέτρου

a tower of 30m in diameter, with an internal core of 15m in diameter, which houses the vertical

30μ με δομικό πυρήνα διαμέτρου 15μ, που εμπεριέχει τις κάθετες διακινήσεις και την υποδομή των

circulation of the building and infrastructure of the mechanical systems. The configuration of the

μηχανικών συστημάτων. Η σύνθεση του πύργου είναι πλήρως τυποποιημένη σε σύνολα των 8

tower is entirely modular in sets of 8 floors per outrigger, making it also possible to manufacture and

ορόφων ανά outrigger, καθιστώντας το δυνατό να κατασκευαστεί και να ανεγερθεί το κτίριο με μια

construct the building in an assembled approach.

συναρμολογούμενη προσέγγιση.

abstract

hexmod

04

02

main analysis

main analysis Some architects and artists of the past, such as

From 1962 to 1964, Peter Cook was also working

the London’s Independent Group, and many

on what was to become another classic

others,

Archigram project. In Plug-in City all elements

praised

the

machine-made,

the

liberation and protection that came about

were expendable and could be dismantled

through co-existing with the machine.

and reassembled. Small living capsules were plugged into megastructural frames. Plug-in City

At this time some students and young architects

even had weather balloons ready to inflate to

began to conceive and talk about urban

block out the unruly and unpredictable climate

developments as organisms within a larger

of the UK. Whilst its individual segments would

organism: the city. The individual pieces of this

become obsolete, the city itself would remain

meta-organism – the buildings – consisted of

vital if new, updated segments could be

skins, spines, tubes and plates, and were

incorporated to replace them.

designed to respond to fluctuations in use for

So in a sense the thick and heavy engineering

accessibility to space, sudden events and the

with its cli-on metallic podding and cranage

changes

in

the

demands

vicissitudes of the weather. Peter Cook called

that so invigorated the architectural debate at

such ideas and propositions the “lost movement

the beginning of the decade disappeared in a

of Bowellism”.

few years in the white heat of technology. It

One of the truly original designers of this period

experimentation, by a disembodied, floating

was Mike Webb. In his work, the Heroic structure,

architecture

where one could see the structure pulled away

transient,

was

replaced, of

at

the

swift-blown

invisible,

vanguard enclosures

ever-evolving

of

“Corn on the Cob”, Arthur Quarmby, 1962

and

electronic

from the surfaces of enclosures and expressing

networks. This is the fundamental lesson to be

itself, it’s circulatory pattern fed in, duct-like, to

learned from Archigram: the heavy and stupid is

this rigid grid. The structure embraced a series of

systematically replaced by the light and smart.

pod-like accretions which looked like they might be moved, re-articulated or added to. Function

One of the most memorable propositions of the

was expressed by the separation of difference,

60’s – the definitive Megastructural model of it’s

and this separation required an articulation of

generation – was Gunther Domenig’s and

the connection and jointing of spaces.

Eilfried Huth’s Graz-Ragnitz project (1965-1969).

Through it’s intricate ordering system, an equally

Other architects explored large-scale urban

complex series of woven circulation, roads,

design; Paolo Soleri’s Mesa City (1959) and

goods,

Ekkehard Schulze-Fielitz’s Space City (1960)

Capsules could be plugged into the system at

were interested in high-density non-prescriptive

many optional points.

living

in

conjunction with

structures.

Two

and

service

runs

was

positioned.

massive support

projects

by

Japanese

Metabolists – Arato Isozaki’s Space City (1960) and

Kisho

Kurokawa’s

Helecoid

–

also

contributed to an evolving aesthetic of huge straddling structures.

Sectional Perspective of “Fun Palace”, Cedric Price, 1964

flexible theoretical concepts

patterns,

05

“Spatial City”, Yona Friedman, 1923

Despite its serious background, Archigram became a synonym for the fusion of pop and architecture. In 1961 the first issue of the magazine Archigram appeared, edited by David Greene, Peter Cook and Michael Webb, in an edition of 300 and printed on large-format paper. It was a lowbudget publication, but highly self-consciously saw itself as the mouthpiece for a young generation of architects, planners and artists, presenting new solutions for existing urban-design problems. For the second issue, published in 1962, Warren Chalk, Dennis Crompton and Ron Herron, who worked together at London County Council, encountered the loose, co-operative group. Joint architectonic projects soon developed out of their work on the magazine, such as the exhibition Living City in London’s ICA, in which Archigram re-staged the City as a living organism. Projects like Walking City, Instant City and Crushicle followed. In 1964, with Plug-in City, Archigram presented the ultimate in megastructure: held by the diagonal struts of the supporting structure and connected by communicating pipes, are a mass of residential towers, office structures, honeycomb theatres and information silos. The buildings are crowned by cranes, with which the individual modules can easily be moved and exchanged.

“Plug-in City”, Archigram, 1962-1964

Alan Boutwell became acquainted with the ideas of the megastructuralists during his studies and was particularly impressed by the thoughts and designs of Archigram. In 1965, his first designs of modular building systems were released, in which he experimented with new technologies and materials. The project of a gigantic linear city that he created together with Michael Mitchell caused a sensation. It spanned on hundred meter high pillars straight across the American continent. Its interior combined all classical functions of urban life and was connected by a complex traffic system that was differentiated by speed, transportation and distances.

“Continuous City of 1,000,000 Human Beings”, Alan Boutwell, 1965

flexible theoretical concepts

Yona Friedman (1923) developed his concept of Ville spatiale, the Spatial City, on the basis of two elementary thoughts: Architecture should only provide a framework, in which the inhabitants might construct their homes according to their needs and ideas, free from any paternalism by a master builder. Furthermore, he was convinced that the progressing automation of production and, resulting from that, the increasing amount of leisure time would fundamentally change society. The traditional structure of the city, according to Friedman, is not equipped for the new society. He suggested mobile, temporary and lightweight structures instead of the rigid, inflexible and expensive means of traditional architecture.

06

Überbauung Ragnitz is one of the outstanding megastructure projects. Compared with the mostly ‚sketch like-fomenting proposals by Hans Hollein, Walter Pichlers or other members of the Viennese and Graz architecture scene it is much more detailed and refers more to actual construction. Customized living units and transportation lines can be integrated into a ‚secondary system’ serving the double purpose of creating a basic spatial structure and hosting the supply network. Parking for automobiles, which were considered a necessary evil, was planned for within the basement of the structure as a concession to contemporary reality.

“Uberbaung Ragnitz”, Eilfried Huth & Gunther Domenig, 1965-1969

In the late fifties Schulze-Fielitz enhanced his ideas of the Space City to a theory of a universal structure. The universal structure had already served as the basis of his competition entry for the Opera building in Essen 1960. Later on he applied the same principles to his competition entries for Berlin-Tegel airport and the Olympic Stadium in Munich (both 1967).

1969 he designed theHabitainer, flexible and transportable accommodations that were established in Turkey, Algeria and on Sao Toma.

In the 70ies and 80ies Schulze-Fielitz realized a number of residential developments, but always returned to his ideas of the Raumstadt, for example in his plan for a Surf+Sail City at the Oosterschelde. In recent years he has mainly concerned himself with geometric theories which relate to his earlier thoughts about a universal structure.

“Uberbaung Ragnitz”, Eilfried Huth & Gunther Domenig, 1965-1969

The Nakagin Capsule Tower, completed in 1972, was designed by Kisho Kurokawa, the youngest Metabolist architect. The building is composed of two concrete core towers and 140 capsules plugged into the towers. All of the capsules were prefabricated and designed to be removable and replaceable. Each of the original capsules, about 10 square meters (approx. 107 square feet), contained various amenities, including: a bed, a desk, a refrigerator, a TV, storage spaces, a toilet and a shower. It was planned as a futuristic niche for modern businessmen in Tokyo.

“Nakagin Capsule Tower”, Kisho Kurokawa, 1972

flexible theoretical concepts

The project Ragnitz does not content itself with the constructive aspects of an urban megastructure. Rather it intends to create adequate spatial structures for a new and more flexible society. Following Bernhard Hafner‘s concept of an “urban architecture”, the conceived spatial structure shall not only depict social interrelations but shall also form the reality of a solidary and liberal city community.

07

Through analysis of various conceptual proposals it was noticed that the relationship that governs the evolution of tall structures can be organized in 3 hierarchies of development: 1. Monolithic Structural Cores with add-on Modular Units In this configuration, there is a clear definition of a structural core with a generic structural design that acts as the infrastructure that receives a number of structurally independent add-on modules in variable configurations that enable the building. It acts as a passive carrier of vertical movement and technical support for the modules (i.e. electricity, plumbing, ventilation) 2. Structurally Independent Stackable Modules In a stackable format, the necessity for a structural core is made obsolete, as the structurally independent modules are conjoined in order to ensure structural integrity as a whole. They are either supplied by a main supply at the base, or they have independent supplies.

3. Modular Structural Infrastructure In modular structures, the structure itself is comprised of pre-designed building blocks that are then deployed in relation to each other to create a structurally unified object. Flexibility is then achieved usually not by incorporating separate modules, but rather by sealing off parts of the structure.

“21st Century Plug-in Housing ”, Y Design Office

21st Century Plug-in Housing | Y Design Office

Structurally autonomous modules fitted into the structure to enable building performance.

Horizontal arrays of units in variable configurations are relayed per floor, with a slight rotation in order to achieve a 360 degree field of view (Double helix spiral setup).

V-Hive | Ben Simmons, Daniel O. Ware, Ginger Watkins, Joseph H. Tiu Growth of unitary hexagonal cells, which cluster, grow, and evolve to form honeycomb colonies in a vertical fashion, and applied to the vertical nature of skyscrapers. By creating a lattice structure to which these cells can attach, the organic germinating nature of city growth is reproduced.

The clustering of individual cells form sky-pod colonies, which themselves become “neighborhoods” or “buildings”, in a vertical urban environment.

The honeycomb is the most efficient geometric structure in terms of using the least amount of material needed to obtain stability. Modular and rigorously structured, yet evolves into an organic whole.

Honeycomb variable modules in generic exo-skeleton. Geometry is based on the structural efficiency of the hexagon.

The configuration of the modules depends, amongst other things, on the required porosity of the structure and the necessity to maintain critical population in order to create a sense of community.

“V-Hive”, Ben Simmons, Daniel O. Ware, Ginger Watkins, Joseph H. Tiu

flexible conceptual proposals

Structural infrastructure containing circulation and electricity plumbing.

08

“Coalesce Skyscraper”, Justin Oh The final height of this skyscraper has not yet been decided, as perpetual development of the project has continued for more than twenty years. Its rich history can be witnessed and analyzed through the changes in the facade, the same way history can be seen in layers of stone or the rings of a tree. The architecture of the skyscraper changes as each firm contributes their own unique design proposals for the next addition to the tower’s elevation – mankind’s skyscraper project of the twenty-first century.

“Coalesce Skyscraper”, Justin Oh

The core of the project is the skyscraper. Unparallel to any skyscraper in the world, the design of this structure is an ongoing collaboration of work from architects on the global scale. The skyscraper rises in phases, depending on the needs and demands of the community. Each phase is produced by a mixture of both local and international architects to create a completely unique design and individual architecture. As the development continues to rise, occupants will begin to inhabit the tower.

1. Minimizes materials.

2. Accommodates variable programs 3. Grows and evolves over time.

These three properties represent the tenets for successful future tower design. Two-Dimensional and Three-dimensional Voronoi tessellations are now commonly applied in architectural concepts as a means of dividing space based on irregular data points. While this results in aesthetically interesting design, the translation into the built environment is ineffective as Voronoi is used to study data relationships instead of structural ones.

The field of protein research developed an accurate formula for defining properties of foam, a natural-world analog of Three-dimensional Voronoi.

Foam is an incredibly lightweight and efficient structure that is the basis of soap films, bone, sponges, and coral, among others. Instead of relying on a scatter of points, it is based on the packing of spheres in the same way that cells aggregate and ossify over time into structural systems. By assigning program to spheres of varying radius (program spheres), the architect packs program according to common requirements such as adjacencies, access to sun, views, etc. The program spheres can then be converted into an accurately modeled Three-dimensional array of irregular planar polygons using scripts designed to follow the protein structure algorithm.

The intersection of irregular polygons creates a structurally sound network of tetrahedral nodes that can be thickened to form the tower infrastructure.

“Voronoi Skyscraper”, Geoffrey Braiman, David Beil

flexible conceptual proposals

“Voronoi Skyscraper”, Geoffrey Braiman, David Beil As a matter of necessity, natural systems continually reorganize until the best possible solution is realized. By analyzing data generated by natural physical phenomenon it is possible to extract mathematical rules that replicate the physics of nature, so rather than conforming to column and slab construction techniques, a skyscraper based on nature results in a streamlined structure that:

09

Vertical Loading Vertical Loading in high-rise buildings is in logic very similar to lower buildings. Dead loads derive from the weight of the construction elements.

For normal office use in high-rise buildings live loads should be taken to vary between 2.0 and 5.0 kN/m2, taking into consideration variable partitioning and higher live loads in the corridor areas.

US-1972

DIN 1055

EC 1

Office Space

2.40

2.00

3.00

Lobbies

4.80

5.00

5.00

Units in kN/m2

Depending on the number of stories, live loads may be reduced for load transfer and the dimensioning of vertical load-bearing elements. However, the reduction of the total live load on a construction element may not exceed 40%.

Horizontal Loading

High-rise buildings are susceptible to oscillation. This means that wind loads should not be viewed as statically equivalent loads, but must be investigated under the aspect of sway behavior. Wind tunnel experiments are usually carried out to determine the influence of the building’s shape on the wind load.

The usual value of the eigenfrequency at which a lateral acceleration can be perceived in high-rise buildings (about 0.1 to 0.2 oscillations per second) lies at around 0.5 percent of acceleration due to gravity. At values between 2 and 4 percent of acceleration due to gravity and oscillations are felt as disturbing, and become unbearable at higher values.

Earthquake Perception Levels

Prevailing Wind

Parameters that induce wind force response:

Alongwind

• Shape + Height of building • Structural Properties (mass, stiffness, damping)

Prevailing Wind

Structural eccentricity between elastic and geometric centre

Torsional

Wind Effects Wind stimuli can be important both in terms of safety and performance of buildings, and in terms of comfort. In the past, the dynamic effect of wind was often the cause for structural failure. Galloping denotes a self-starting oscillation, produced by a pressure field in an oscillating body as a result of its relative movement in reaction to the oncoming flow.

Under the action of wind, tall buildings oscillate simultaneously in the alongwind, crosswind and torsional directions. While codes and standards have mostly covered the alongwind loads (using strip theories in terms of gust wind loading factors), the crosswind and torsional loads cannot be treated in such a manner, as they are mostly owing to pressure fluctuations and their distribution.

Crosswind

10% Eccentricity > 100% mean twist, 40-50% dynamic twist

Wind Pressure Distribution

Design Principles GOALS G1 – stability in case of earthquake, wind, etc.

G2 – protection of persons/equipment in building from surface effects (traffic, etc.)

G3 – protection of persons/equipment in building from direct effects on building (earthquake, wind, etc.)

MEASURES M1 – “detuning” of building to prevent resonance phenomena M2 – strengthening the building to increase resistivity M3 – employing additional passive elements to influence oscillation M4 – employing active elements to influence oscillation G1

G2

G3

M1

+

+

+

M2

+

-

-

M3

+

-

+

M4

+

-

+

Tall buildings have resonant dynamic response for along and across wind that is very significant. Torsional response is mostly owing to the geometry of the given building, and is caused by aerodynamic forces produced by non-uniform pressure distribution along the faces of the building., creating coupling moments.

Types of wind design • Environmental wind studies (effect of the building on the enviroment) • Wind Loads on Façade • Wind Loads for Structure

Dynamic wind design is governed mainly by serviceability response (peak accelerations and deflections on the top floors).

Design Criteria • Stability against overturning and/or sliding and/or uplift • Strength of the structural components • Serviceability (inter-storey and overall deflections)

+ measure suitable for achieving goal - measure not very helpful

Control of Sway Accelerations: Wind response is relative to both mass and stiffness – response acceleration may be reduced by increasing these parameters

This is in conflict with earthquake design optimization, where loads and ground acceleration is minimized by reducing mass and stiffness

structural demands in tall buildings

Owing to the large influence of horizontal stiffening on structure design, the calculation of lateral loads should be carefully scrutinized. The lateral loads generally arise from unexpected deflections, wind and earthquake loads.

10

Designing a high rise building has its challenges.

Different structural systems have been developed to control the lateral displacement of high rise buildings. One of these systems is called the outrigger which decreases both the horizontal movement of the structure and the moment on the foundation of the structure.

However the location of the outriggers has an immense influence on the efficiency of the structure. Outrigger optimization is a significant challenge.

The high rigidity of the load-bearing elements and their coupling with the façade columns mean that the outriggers are able to return the deformed core to vertical and thereby reduce the horizontal deformation of the building.

Outrigger structures are highly stressed loadbearing systems, usually constructed in reinforced concrete to be able to withstand concentrated forces. They can also be used to connect two independent cores rigidly, thereby increasing the total stiffness quite considerably.

In the late nineteenth century, early tall building developments were based on economic equations – increasing rentable area by stacking office spaces vertically and maximizing the rents of these offices by introducing as much natural light as possible. In order to serve this economic driver, new technologies were pursued that improved upon the conventional load-bearing masonry walls that had relatively small punched openings.

Effectively resists bending by exterior columns connected to outriggers extended from the core. Outrigger Structure does not add shear resistance.

When individual cores are too slender to assume the horizontal loads they can be coupled to one another, or to façade columns, using additional boom girders (outriggers). However, in contrast to coupled shear walls, the coupling occurs only on individual stories and is not continuous over the height of the building. This leads to a liberal treatment in the design of the floor plan. Usually the cantilevers are incorporated into machine floors, so that restraints on floor usage do not arise.

Efficiently resists lateral shear by axial forces in diagonal members. Complicated joints.

comparison of structural systems

The study of the response of tall buildings to wind has become more critical with the increase of super tall buildings in major cities around the world. Outrigger-braced tall building is considered as one of the most popular and efficient tall building design because they are easier to build, save on costs and provide massive lateral stiffness. Most importantly, outrigger-braced structures can strengthen a building without disturbing its aesthetic appearance and this is a significant advantage over other lateral load resisting systems.

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Killesberg Tower, Germany

Killesberg Tower, Germany

materialized examples

The Killesberg Tower designed by JÜrg Schlaich was built in 2000, in Stuttgart, Germany. It features a large spiral staircase suspended by a cable structure on a central support. This design incorporates two concepts of structural design – first, it embraces the pre-mentioned examples, diagonally braced exterior frames and diagrids, and secondly, it allows for the cable-oriented, lightweight thinking of bridge engineering to improve the designs’ efficiency.

Swiss Re Building, UK Another type of exterior structure is a diagrid system. With their structural efficiency as a varied version of the tubular systems, diagrid structures have been emerging as a new aesthetic trend for tall buildings in this era of pluralistic styles. Early designs of tall buildings recognized the effectiveness of diagonal bracing members in resisting lateral forces. Most of the structural systems deployed for early tall buildings were steel frames with diagonal bracings of various configurations such as X, K, and chevron.

Swiss Re Building, UK

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For additional core stiffness, the lowest floors from basement to the 8th floor have concrete shear walls cast between core columns in addition to diagonal braces.

The most of the lateral loads will be resisted by a combination of braced cores, cantilevers from the core to the perimeter, the super columns and the Special moment resisting frame (SMRF).

The cantilevers (horizontal trussed from the core to the perimeter) occur at 11 levels in the structure. 5 of them are double storey high and the rest single storey.

16 of these members occur on each of such floors.

The balance of perimeter framing is a sloping Special Moment Resisting Frame (SMRF), a rigidly-connected grid of stiff beams and H shape columns which follows the tower’s exterior wall slope down each 8 story module.

At each setback level, gravity load is transferred to ‘super-columns’ through a story-high diagonalized truss in the plane of the SMRF.

To allow the city’s sprawl and to be less restrictive at the base of the building, some examples were sought that could act as references. It was decided that the first set of floors closer to the ground up to the first outrigger would consist only of the structural core, in order to release the lower levels to the rest of the city, and for individual architectural expression to manifest at street level.

Above the 26th floor, only two exterior super-columns continue to rise up to the 91st floor, so the SMRF consists of 600 mm deep steel wide flange beams and columns, with columns sized to be significantly stronger than beams for stability in the event of beam yielding.

materialized examples

Each 7-story of SMRF is carried by a story-high truss to transfer gravity and cantilever forces to the super-columns, and to handle the greater story stiffness of the core at cantilever floors.

Taipei 101, Taipei

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Hexagon Angles

Hexagonal Grid Density | Vertical | Number of Hexagons within the Predefined Height of Exoskeleton Tube

By using the Grasshopper plug-in for Rhinoceros, it was decided to create an algorithm that would allow the generation of a number of variations in the shape, scale and density of the hexagonal grid, to enable us to test and optimize the architectural expression and structural efficiency of the exoskeleton tube. The parameters that are configurable are the angles of the hexagonal members, the number of faces of the exoskeleton tube, the scale of the hexagons within the predefined height, the total exoskeleton height and the thickness of the structural members.

design of structure

Hexagonal Grid Density | Horizontal | Number of Exoskeleton Faces

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design of structure

T: 1.74s F: 0.57Hz Maximum Deflection: 0.0155m Maximum Rotation: 0.00005 rad

design of structure

CASE 1 Uniform Exoskeleton density with outrigger trusses divided in 8 floors.

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T: 1.50s F: 0.67Hz Maximum Deflection: 0.0168m Maximum Rotation: 0.00005 rad

with

outrigger

trusses

design of structure

CASE 2 Non-Uniform Exoskeleton density divided in 2, 4, 8 and 8 floors.

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T: 1.41s F: 0.71Hz Maximum Deflection: 0.017m Maximum Rotation: 0.00006 rad

with

outrigger

trusses

design of structure

CASE 3 Non-Uniform Exoskeleton density divided in 2, 2, 4 and 8 floors.

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The morphology of the honeycomb structure on the exterior was generated based on a number of factors. The first and foremost set of factors on the selection process was architectural. The search for a morphology that would optimize a number of architectural factors, such as day lighting, natural ventilation, less space consuming connection of independent modules and stronger cross bracing structure (leading to more efficient use of structural material and hence achieve a more lightweight design). By using a hexagonal form, it was possible to pack the plug-in modules more densely, hence making it possible to pack a larger number within the same volume. The length of the modules is variable between 8m and 12m in length, and it is possible to house up to 16 units per floor, residing on a tower of 30m in diameter, with an internal core of 15m in diameter, which houses the vertical circulation of the building and infrastructure of the mechanical systems. The configuration of the tower is entirely modular in sets of 8 floors per outrigger, making it also possible to

unit morphology

manufacture and construct the building in an assembled approach.

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Connections are established axially that secure the external frame to the core. The external frame acts as a tension bearing mechanisms that connect the outrigger structures that protrude from the core, while at the same time acting as support for the connection of the addon units that are attached externally.

Glazing is inserted in the open faces of the frame structure, and is detachable upon connecting the external units.

3-Dimensional supports are used to connect the faces of the honeycomb grid structure, while at the same time anchor the edges of the additional units for added support.

A Tension/Compression system of tension/compression rods is designed to connect the supports to the grid , to ensure the rigidity of the frame body.

construction details

A monolithic structural tube core is designed in the middle of the building, that encloses the staircases for vertical movement, the service areas of the building, and the piping for the mechanical support that runs through the floors to the add-on units.

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elevation

elevators mechanical system chute

internal corridors

bathrooms staircases

The elevators and staircase are attached to the interior structural core externally and internally respectively. The space between the elevators and the external frame acts as a circular corridor thas is diametrically conected through the middle of the structural core.

visualization

external modular units

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visualization

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Plan variations

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Plan variations

03

appendix

presentation layouts

appendix

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presentation layouts

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presentation layouts

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presentation layouts

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presentation layouts

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presentation layouts

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presentation layouts

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presentation layouts

04

bibliography and web resources

bibliography bibliography • “Visionary Architecture: Blueprints of the Modern Imagination”, Neil Spiller, Thames & Hudson, 2007 • “Evolo: Skyscraper for the XXI Century”, Carlo Aiello, Evolo Publishing, 2008 • “Reinventing the Skyscraper: A Vertical Theory of Urban Design”, Ken Yeang, Wiley-Academy, 2002 • “Performative Architecture – Beyond Instrumentality”, Branko Kolarevic & Ali M. Malkawi, Spon Press, 2005 • “High-Rise Manual”, Johann Eisele & Ellen Kloft, Birkhauser, 2002 • “The Application of Statistical Concepts to the Wind Loading of Structures”, A.G. Davenport, Proc. Inst. Of Civil Engineers, 1961

• “Morphogenesis and Structural Optimization of Shell Structures with the aid of a Genetic Algorithm”, Alberto Pungale & Mario Sassone, Politecnico di Torino, Italy • “Connecting Engineering and Architecture Through Structural Topology Optimization”, Lauren L. Stromberg, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, USA • “Nature Inspired Creative Design – Bringing Together Ideas from Nature, Computer Science, Engineering, Art, Design”, Thorsten Schnier, Cercia, School of Computer Science, University of Birmingham, UK • “Bio-inspiration: Learning Creative Design Principia”, Tomasz Arciszewsky, George Mason University, Fairfax, USA • “The New Structural Concept Tensairity: Basic Principles”, R.H. Luchsinger, Prospective Concepts AG, Glattbrugg, Switzerland • “Aerodynamic Loads on Tall Buildings: Interactive Database”, Yin Zhou, Dept. of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN, USA • “Gust Loading Factors for Design Applications”, Yin Zhou, Dept. of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN, USA • “Recent Applications of Structural Control Systems to High-Rise Buildings”, Toshiyuki Tanaka, Engineering Section, Business Promotion Department, Osaka Office, Takenaka Corporation • “Alongwind Static Equivalent Wind Loads and Responses of Tall Buildings”, Yin Zhou, Dept. of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN, USA • “Structural Developments in Tall Buildings: Current Trends and Future Prospects”, Mir M. Ali and Kyoung Sun Moon, School of Architecture, University of Illinois at Urbana-Champaign, IL, USA • “The Role of Aerodynamic Modifications in the Form of Tall Buildings Against Wind Excitation”, H. Emre ILGIN and M. Halis GUNEL • “Comparative Study of Structural Systems for Tall Buildings”, M.M. Hussein, Structural Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt • “Wind Loading on Tall Buildings”, P. Mendis, University of Melbourne, Australia • “Recommendations for the Seismic Design of High-Rise Buildings”, CTBUH, Michael Willford, Andrew Whittaker, Ron Klemencic • “Wind Issues in the Design of Tall Buildings”, Peter A. Irwin, Los Angeles Tall Building Structural Design Council • “Mitigation of Motions of Tall Buildings with Specific Examples of Recent Applications”, Ahsan Kareem, Dept. of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN, USA • “Serviceability Limit States Under Wind Load”, Lawrence G. Griffis • “Study of Wind Flow around Tall Buildings: Case Study of Wind Flow Through High-Rise Apartment’s Central Shaft”, A.Q.M. Abdullah, Department of Architecture, Brac University, Dhaka, Bangladesh • “Design of Tall Buildings – Preliminary Design and Optimization”, P. Jayachandran, Worcester Polytechnic Institute, Worcester, Massachusetts, USA • “Emergent Engineering: A Radical Paradigm Shift”, Mihaela Ulieru, Faculty of Computer Science, University of New Brunswick, Canada

bibliography and web resources

papers

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