The Singapore Engineer January 2020 by The Singapore Engineer

THE MAGAZINE OF THE INSTITUTION OF ENGINEERS, SINGAPORE

THE SINGAPORE ENGINEER

www.ies.org.sg

January 2020 | MCI (P) 105/03/2019

COVER STORY: Thomson-East Coast Line Stage 2 almost complete

PLUS

CONSTRUCTION PROSPECTS: Singapore’s construc on demand for 2020 expected to remain strong CONCRETE TECHNOLOGY: Enhancing standard test approach to be er reflect applica on requirements CONSTRUCTION LAW: Payment Claims – En tlements and Limita ons

I BUILD ON EXPERIENCE I see the possibilities my career can bring. Because a career in the built environment is one that can create direct yet far-reaching impact. At BCA, my work on policy measures help to drive change in the built environment sector and make a positive difference. We constantly shape the landscape to prepare for the future of Singapore, rally the built environment sector to achieve farreaching goals beyond today, and improve the living environment for Singaporeans from all walks of life. Be part of this transformation, and join us for a fun and meaningful career. Find out more about our career opportunities at www.bca.gov.sg

Lim Yong Xian Senior Engineer

CONTENTS FEATURES COVER STORY

11 Thomson-East Coast Line Stage 2 almost complete The 43 km Thomson-East Coast Line will open in five stages star ng from this year.

CONSTRUCTION PROSPECTS

14 Singaporeâ&#x20AC;&#x2122;s construc on demand for 2020 expected to remain strong The built environment sector is urged to look ahead, invest in digitalisa on and innova on-driven growth, and groom local talent.

CONCRETE TECHNOLOGY 17 Enhancing standard test approach to be er reflect applica on requirements Prac cal adjustments to the specifica ons can lead to be er outcomes.

CONSTRUCTION LAW 24 Payment Claims - En tlements and Limita ons A brief summary of the decision by the Court of Appeal on a case rela ng to the Building and Construc on Industry Security of Payment Act, and key takeway points, are provided.

President Prof Yeoh Lean Weng Chief Editor T Bhaskaran t_b_n8@yahoo.com

THE SINGAPORE ENGINEER January 2020

Publica ons Manager Desmond Teo desmond@iesnet.org.sg Publica ons Execu ve Queek Jiayu jiayu@iesnet.org.sg

Editorial Panel Dr Chandra Segaran Prof Simon Yu Dr Ang Keng Been Dr Victor Sim Mr Syafiq Shahul Media Representa ve Mul Nine Corpora on Pte Ltd sales@mul 9.com.sg

Design & layout by 2EZ Asia Pte Ltd Cover designed by Irin Kuah Cover images by Land Transport Authority Published by The Ins tu on of Engineers, Singapore 70 Bukit Tinggi Road, Singapore 289758 Tel: 6469 5000 I Fax: 6467 1108 Printed in Singapore

www.ies.org.sg

THE STRUCTURAL AWARDS 2019 27 Winning projects represent supreme global engineering feats The Ins tu on of Structural Engineers (IStructE) announced the winners in November last year.

INFRASTRUCTURE PLANNING 34 The future of infrastructure will be smart With the changing urban landscape, ci es must transform to be more accessible and produc ve.

RECYCLING TECHNOLOGIES 36 Technologies for the diﬀerent processing stages in asphalt recycling Reclaimed asphalt pavement (RAP), is a valuable resource.

PROJECT APPLICATION 38 Construc ng and finishing the new Istanbul airport A wide range of chemical products was used in the first phase.

41 Sweden’s biggest road and tunnel project A 21 km motorway bypass is being constructed to relieve traﬃc in Stockholm.

REGULAR SECTIONS 04 10 44 48

INDUSTRY NEWS EVENTS PRODUCTS & SOLUTIONS IES UPDATE

The Singapore Engineer is published monthly by The Ins tu on of Engineers, Singapore (IES). The publica on is distributed free-of-charge to IES members and aﬃliates. Views expressed in this publica on do not necessarily reflect those of the Editor or IES. All rights reserved. No part of this magazine shall be reproduced, mechanically or electronically, without the prior consent of IES. Whilst every care is taken to ensure accuracy of the content at press me, IES will not be liable for any discrepancies. Unsolicited contribu ons are welcome but their inclusion in the magazine is at the discre on of the Editor.

THE SINGAPORE ENGINEER January 2020

INDUSTRY NEWS

ARUP JOINS AS A PIONEER SIGNATORY OF ‘CONSTRUCTION DECLARES’ Arup, a global planning, design, engineering and business consultancy, recently announced that it will be joining 11 other local architects and engineers to sign up to Construc on Declares - a global pe on uni ng all strands of construc on and the built environment. Construc on Declares is both a public declara on of our planet’s environmental crises and a commitment to take posi ve ac on in response to climate breakdown and biodiversity collapse. Singapore is the first Asian country to join Construc on Declares with both architects and structural engineers as founding signatories. The declara on statements can be found on Singapore Structural Engineers Declare and Singapore Architects Declare. The founding members of the Singapore pe on include the architectural firms CSYA, DP Architects, Forum Architects, Guz Architects, HASSELL, SCDA and WOHA, and the structural engineering firms Arup, DP Engineers, RSP, Web Structures and WSP. Tan Yoong Heng, Arup Singapore’s Oﬃce Leader said, “Shaping a be er world with social purpose has always been the founda on of Arup’s philosophy and work. Naturally, we are proud and mo vated to support Construc on Declares. It is important that engineers and architects come together as a collec ve and commit

to put posi ve environmental outcomes at the core of our working prac ces. I hope this ini a ve will inspire others in Singapore and the region, to strive for a more sustainable and resilient future”. Singapore, although somewhat protected by its equatorial loca on and its ‘City in a Garden’ policies, has been experiencing the twin crises of climate breakdown and loss of biodiversity with increasing periods of drought and higher temperatures. The Climate Emergency is the most serious issue of our me, and buildings and construc on play a major part - accoun ng for nearly 40% of energyrelated carbon dioxide (CO2) emissions while also having a significant impact on our natural habitats. The Climate Declara on is a call to ac on for everyone working in construc on and the built environment to meet the needs of our socie es without breaching the earth’s ecological boundaries. This will demand a paradigm shi in behaviour. If we are to reduce and eventually reverse the environmental damage we are causing, we will need to re-imagine our buildings, ci es and infrastructures as indivisible components of a larger, constantly regenera ng and self-sustaining system. Arup has more than 16,000 staﬀ working in over 140 countries around the globe. The firm’s Singapore oﬃce was established in 1968.

New Rail Manpower Development Package announced Coordina ng Minister for Infrastructure and Minister for Transport, Mr Khaw Boon Wan, unveiled a SGD 100 million Rail Manpower Development Package (RMDP) at a public transport workers’ event late last year. Targeted at railway workers, the RMDP is co-developed by LTA with the public transport operators (PTOs) and the Na onal Transport Workers’ Union (NTWU). It aims to expand the rail workforce and accelerate its transforma on over the next five years, in order to prepare for the opera on of an expanded and more complex rail system. Over the next decade or so, LTA will be adding three new rail lines - the Thomson-East Coast Line, Jurong Region Line and Cross Island Line. This will increase the length of the rail network by about 130 km, bringing the total network length to about 360 km in 2030. This expansion take place amidst the upgrading of ageing rail assets across exis ng lines to sustain rail reliability and the adop on of new opera ons and maintenance technologies, such as remote condi on sensors and augmented reality, to achieve greater cost eﬃciencies.

THE SINGAPORE ENGINEER January 2020

The RMDP enhances exis ng training programmes oﬀered by the PTOs, as well as ini a ves supported by Workforce Singapore and SkillsFuture Singapore. It comprises three key components, the first of which being incen ves for manpower development, to encourage PTOs to expand and accelerate their training in future-relevant technologies and skillsets in emerging areas such as data analy cs and condi on-based maintenance. Around 3,000 rail workers are expected to benefit. Second, new SGRail Industry Scholarships and in-service sponsorships will also be established to a ract and retain talent to become future industry leaders. The scholarships, in par cular, are expected to help some 400 students and workers, and will be applicable for programmes at ITE and the various Ins tutes of Higher Learning. Third, investments will be made in training hardware equipment like simulators or virtual reality equipment that help support more hands-on training in a safe and controlled environment.

INDUSTRY NEWS

RAMBOLL ACQUIRES WEB STRUCTURES Ramboll, a leading engineering, design and consultancy, founded in Denmark in 1945, has joined forces with Singapore-based Web Structures, an interna onallyacclaimed civil, structural, geotechnical, sustainable and environmental engineering consultancy delivering highquality solu ons across the globe, to offer innova ve integrated design in Southeast Asia. The acquisi on strengthens Ramboll’s posi on in the region, adding 120 experts to its Buildings market, from 1 January 2020. “We are very excited to acquire Web Structures. It underpins our commitment to Asia and is integral to our interna onal growth strategy”, stated Richard Beard, Managing Director, Global Buildings and Middle East & Asia Pacific, Ramboll. Now with more than 240 colleagues across Southeast Asia, Ramboll can offer integrated services across the built environment. “Teaming with Web Structures fits in perfectly with our Singapore Hub strategy. Ramboll is now truly a world-class, full-service engineering consultancy in Singapore, offering innova ve sustainable solu ons across Buildings, Water, Environment and Transport across the region”, stated Leonard Ng, Country Director, Singapore Hub, Ramboll.

Web Structures Since its incep on in 1996, Web Structures has been at the cu ng edge of innova ve design, carving a niche for itself. Employing diverse talent from the UK, Europe and Asia, and with oﬃces in Singapore, Kuala Lumpur, Shanghai and London, the company will con nue to operate under the same name, overall management structure and design ethos. With strong exper se in high-rise, luxury resorts and high-end residen al buildings, oﬀering specialist design services, Web Structures has executed over 650 projects in more than 28 countries. Web Structures projects include high-rise buildings like the award-winning Ardmore Residence in Singapore where the structure is parametrically integrated with the architectural form. Web Structures has delivered iconic projects in Singapore and Malaysia, such as the Mediacorp Campus in Singapore; the Grand Hya Hotel in Kuala Lumpur, Malaysia; and the Four Seasons Resort in the Seychelles.

“We see this as a great pla orm to drive an integrated design philosophy where architecture and engineering are blended to oﬀer new opportuni es for value crea on for clients across Ramboll’s 4,500 building designers”, said Dr Hossein Rezai, Founding Director, Web Structures. “Ramboll’s impressive environmental creden als lted the balance for us. At these mes of climate crisis and serious threat to biodiversity, Ramboll’s responsible a tude towards the environment is commendable. We are joining forces to work harder together to achieve these goals through design”, he added.

Ramboll Ramboll employs more than 16,000 experts globally and has strong representa on in the Nordic countries, UK, North America, Con nental Europe, Middle East and Asia Pacific. With 300 oﬃces in 35 countries, Ramboll combines local experience with a global knowledge base, constantly striving to achieve inspiring and exac ng solu ons that make a genuine diﬀerence to clients, the end-users, and society at large. Ramboll works across following markets: Buildings, Transport, Planning & Urban Design, Water, Environment & Health, Energy and Management Consul ng. Ramboll has been present for almost 20 years in Singapore delivering high-end solu ons within bluegreen infrastructure, environment & health, energy, building and transport domains. The company has done work on the Mandai Nature Safari Park and the iMax Solibox Modular Building System in Singapore. 06

THE SINGAPORE ENGINEER January 2020

The Grand Hya Hotel in Kuala Lumpur, Malaysia, is one of the projects delivered by Web Structures. Image by CEphoto, Uwe Aranas.

INDUSTRY NEWS

SINGAPORE NAMED TOP INVESTMENT MARKET

IN ASIA PACIFIC Singapore is the best prospect in the Asia Pacific region for investment according to Emerging Trends in Real Estate Asia Pacific 2020, a real estate forecast jointly published by the Urban Land Ins tute (ULI) and PwC. Singapore witnessed a surge in transac ons in the first half of 2019, with most ac vity driven by cross-border capital, and volumes in the second half of the year are expected to be strong. Today, the oﬃce sector in the market has largely absorbed the oversupply of recent years. Tokyo, Sydney and Melbourne are men oned below Singapore in the list of top five markets for investment prospects while Ho Chi Minh City is listed in third place.

Among the trends cited in the report are the following: • Challenges posed by geopoli cs, par cularly trade wars. • A shi back to urban cores as safe havens. • Broad adop on of sustainable development prac ces. • A more cau ous view of co-working. • The reinven on of retail. • Increased services for building occupants. • A rising interest in the newest niche sectors such as cold storage and last-mile fulfillment centres. • The impact of climate risk on real estate investments. • A growing investment in property technology.

THE SINGAPORE ENGINEER January 2020

INDUSTRY NEWS

NEW RESEARCH LOOKS TO ENABLE NEW WAYS OF

DESIGNING COMPLEX CONCRETE STRUCTURES A new research project pushes state-of-the-art design by enabling finite element limit analysis for solid concrete structures, resul ng in significant me, material and cost savings, improved constructability and fewer environmental impacts. “With the current state of aﬀairs, uncertain es and disputes among engineers are o en encountered in prac ce, regarding the actual load bearing capacity of solid concrete structures and the actual amount of minimum reinforcement that is required to ensure suﬃcient duc lity”, explained Professor Linh Cao Hoang of the Technical University of Denmark (DTU), the Project Manager of the research project.

component in concrete - has a massive carbon footprint and contributes to about 7% of global CO2 emissions. “With the outcome of the research project, we will poten ally make it easier to op mise the design of solid reinforced concrete structures in the future, therefore minimising the quan es of materials needed, such as cement. Thus, we can provide clients with more sustainable designs that minimise cost and environmental impacts”, stated Mr Jesper Asferg, Vice President in COWI’s Bridges Interna onal Department and part of the Steering Group for the research project. The three-year project is a collabora on between DTU Civil Engineering and Danish engineering consultancy COWI.

He added that the uncertain es could have major societal and economic consequences while also preven ng be er material u lisa on in the design. Consequently, the project will seek to develop a theore cal basis for computer-based rigid-plas c analysis and design of solid reinforced concrete structures; uncover new knowledge on the mechanical behaviour of reinforced concrete in the tri-axial stress states; enhance the knowledge of necessary duc lity; and provide valuable empirical insight into the behaviour of solid 3D structures through full-scale tes ng. One main challenge that the industry currently faces is the conserva sm in the design methodology and the compromise between design me and material quan es. However, further op misa on of the designs for large concrete structures could reduce the environmental impact from major infrastructure schemes as cement - a key

Every year, new structures are being built around the world to span further, reach higher and extend wider. A new research project from DTU will look into how contemporary challenges can be met in a sustainable manner.

New resources launched to help global policy-makers plan be er infrastructure A new global policy programme will help decision-makers grappling with the challenge of designing and delivering infrastructure for the long-term benefits of communi es around the world. The Enabling Be er Infrastructure programme oﬀers insights to governments and decision-makers around the world on how to best plan and deliver infrastructure which achieves the most eﬀec ve social and economic outcomes. A report, produced by the Ins tu on of Civil Engineers (ICE) as part of the programme, is a primer for those interested in enabling be er infrastructure around the world. The report iden fies 12 key principles for decision-

THE SINGAPORE ENGINEER January 2020

makers to use as a straigh orward guide to the best ways to plan, implement and deliver major infrastructure. They include: • Iden fying strategic objec ves • Crea ng a na onal infrastructure strategy • Conduc ng cost-benefit analyses • Iden fying private sector involvement Along with a new resource hub on ICE’s website, it brings together case studies, advice and expert insight into how governments can undertake the process of priori sing and planning infrastructure. This report and the developing resource hub will become a useful ‘one-stop shop’ resource for decision-makers across the world to use.

INDUSTRY NEWS

ELON MUSK’S TUNNELLING COMPANY COMMENCES FIRST UNDERGROUND PEOPLE MOVER PROJECT IN LAS VEGAS The Boring Company (TBC), founded by billionaire technopreneur Elon Musk, has begun tunnelling work on The Las Vegas Conven on Center’s (LVCC) underground people mover. The project, which will transport conven on a endees throughout the 200-acre campus when completed, is the first commercial endeavour for TBC. “Our collabora on with The Boring Company con nues to elevate the innova ve experiences we oﬀer our visitors and will ensure that our expanded conven on facili es are among the most tech-forward in the world. We took the concept of u lising the underground people mover from an idea on paper to tunnelling in less than a year, demonstra ng our board’s willingness to embrace bold, new ideas with the poten al to change the face of transporta on in Southern Nevada and beyond”, said Mr Steve Hill, CEO of the Las Vegas Conven on and Visitors Authority.

The system will be designed for ridership of at least 4,400 passengers per hour and is scalable depending on conven on a endance. When completed in January 2021, the underground people mover will comprise two vehicular tunnels with an expected total length of approximately 1 mile (1.6 km) each. The system will have the poten al in the future to expand and link key visitor a rac ons throughout Las Vegas, such as Downtown Las Vegas, Las Vegas Strip, and McCarran Interna onal Airport

The USD 52.5 million underground people mover will include three passenger sta ons connec ng the exis ng 3.2 million 2 of conven on space with the LVCC’s new 1.4 million 2 West Hall currently under construc on, as part of a USD 1.52 billion expansion and renova on. The innova ve transporta on system will allow conven on a endees to be transported across the LVCC’s 200-acre campus in just over one minute, in all-electric Tesla vehicles capable of holding between 3 and 16 people.

The drill head for the tunnel boring machine is lowered into the work area, in prepara on for tunnelling opera ons. Image by Mark Damon/ Las Vegas News Bureau.

The underground people mover will run under the Las Vegas Conven on Center (in the centre of the image, with white roofing), from the South Hall to the new West Hall expansion. Image by The Boring Company. THE SINGAPORE ENGINEER January 2020

EVENTS

FINAL CALL TO ENTER

LAFARGEHOLCIM AWARDS

Entries to the 6th Interna onal LafargeHolcim Awards for Sustainable Construc on will close on 25 February 2020. The compe on seeks projects by professionals as well as bold ideas from the Next Genera on that combine sustainable construc on solu ons with architectural excellence. The LafargeHolcim Awards are given to projects and concepts from architecture, engineering, urban planning, materials science, construc on technology, and related fields. Organised by the LafargeHolcim Founda on, the compe on for the Awards takes place in parallel across five geographic regions - each with its own jury of renowned and independent specialists. The regional juries are headed by Jeanne e Kuo, Karamuk Kuo Architects, Switzerland (Europe); Reed Kroloﬀ, Illinois Ins tute of Technology, USA (North America); Loreta Castro Reguera, Taller Capital, Mexico (La n America); Mariam Kamara, atelier masōmī, Niger (Middl2e East Africa); and Nirmal Kishnani, Na onal University of Singapore (Asia Pacific).

Two categories with diﬀerent requirements The main category of the compe on is open to architects, planners, engineers, project owners, builders and construc on firms, showcasing sustainable responses within contemporary building and construc on. Projects must have reached an advanced stage of design, have a high probability of execu on, and may not have started construc on before 1 January 2019. In addi on, students and young professionals (aged 30 years or younger) may submit visionary concepts and bold ideas in the Next Genera on category of the compe on. Submissions may be at an early stage of design - including research and design studio work. 10

THE SINGAPORE ENGINEER January 2020

Entry to the compe on is free and must be made in English using a web-based form: www.lafargeholcim-awards.org/enter

‘Target issues’ for sustainable construc on Submissions are evaluated according to five ‘target issues’ for sustainable construc on - that aim to clarify principles for sustaining the human habitat for future genera ons. The ‘target issues’ cover innova on and transferability, ethical standards and social inclusion, resource and environmental performance, economic viability and compa bility, as well as contextual and aesthe c impact.

Global LafargeHolcim Awards compe

The winners will be announced in the second half of 2020 at Awards ceremonies in each region. The main winners then compete for the global LafargeHolcim Awards in 2021, to be evaluated by a global jury headed by Hashim Sarkis, Massachuse s Ins tute of Technology, USA and curator of the 2020 Venice Biennale of Architecture.

LafargeHolcim Founda on Since 2003, the LafargeHolcim Founda on for Sustainable Construc on raises awareness of the important role that architecture, engineering, urban planning, and the building industry have in achieving a more sustainable future. The founda on expresses the commitment of its sponsor LafargeHolcim to drive sustainability in building and construc on. LafargeHolcim is a global leader in building materials and solu ons.

COVER STORY

THOMSON EAST COAST LINE STAGE 2 ALMOST COMPLETE The 43 km Thomson-East Coast Line will open in five stages star ng from this year to becoming completely opera onal in 2024.

TEL2

TEL2 comprises six sta ons from Springleaf to Caldeco , with two interchange sta ons at Bright Hill and Caldeco . The 43 km Thomson-East Coast Line (TEL) is Singapore’s sixth MRT line, adding 32 new sta ons to the exis ng rail network, with eight interchange sta ons in total.

The second stage of the Thomson-East Coast Line (TEL2) is about 90% complete, and on track to open in the later part of 2020. TEL2 comprises six sta ons from Springleaf to Caldeco , with two interchange sta ons at Bright Hill and Caldeco . Bright Hill sta on will link to the future Cross Island Line, while Caldeco sta on will link to the existing Circle Line (CCL). The 43 km Thomson-East Coast Line (TEL) is Singapore’s sixth MRT line, adding 32 new sta ons to the exis ng rail network, with eight interchange sta ons in total. The line will open in five stages star ng from this year to 2024. The first stage of TEL (TEL1), made up of Woodlands North, Woodlands, and Woodlands South MRT sta ons, will begin passenger service on 31 January 2020. About 100,000 households will benefit from TEL1 and

TEL2, as they will be within a 10-minute walk from one of the nine sta ons. These residents will be able to experience travel me savings of up to 50%. For example, a Sin Ming resident travelling to Republic Polytechnic will have the journey me halved, from 50 minutes to 25 minutes. When fully opera onal in 2024 (except for Founders’ Memorial Sta on which will open in tandem with the memorial), the TEL is expected to serve approximately 500,000 commuters daily in the ini al years, rising to about 1,000,000 commuters in the longer term. Besides enhancing connec vity between the northern, central, and eastern parts of Singapore, the TEL will strengthen the resilience of the rail network by providing alterna ve travel routes for commuters on other lines. As the TEL runs parallel to the North-South Line (NSL), it will also help to reduce reliance and crowding on the NSL. THE SINGAPORE ENGINEER January 2020

COVER STORY

Springleaf Sta on Springleaf Sta on is located along Upper Thomson Road, between Thong Soon Green and Springleaf Road. LTA took steps before and during the construc on of Springleaf Sta on to minimise the impact on nearby shop tenants and residents, which included briefing them of the works early on. LTA also worked closely with Singapore PowerGrid to ensure that its cable tunnel, which runs through Springleaf Sta on, could be constructed without interrup ons.

Interior of TEL Springleaf sta on.

Lentor Sta on The loca on of Lentor Sta on is adjacent to the residenal areas. Residents of Lentor Estate and Teacher’s Estate can soon look forward to greater accessibility to the city centre via this sta on. To minimise impact to nearby residences and high-rise developments, top-down construc on was adopted for the construc on of the sta on box and entrances. Extensive studies were conducted to iden fy the network of u lity services located within the work zone, to prevent any disrup ons that could aﬀect the neighbouring estates.

bring rail connec vity to schools, community ameni es and residen al developments in the Kebun Baru Estate, such as CHIJ St Nicholas Girls School, Mayflower Secondary School, Ang Mo Kio Primary School and the Kebun Baru Community Club. As the sta on is situated on a sloping terrain directly underneath Ang Mo Kio Avenue 4, surrounded by densely-built residen al developments, mul ple stages of traﬃc diversion had to be implemented to facilitate the construc on of the sta on while minimising inconvenience to the public.

TEL Mayflower Sta on Entrance G.

Bright Hill Sta on Bright Hill Sta on is located along Sin Ming Avenue. The sta on’s entrance loca ons were chosen to serve residents of Sin Ming Garden, Faber Garden and Gardens at Bishan, as well as Ai Tong Primary School. The sta on provides residents and students direct connec vity in the future to the city centre as well as the eastern region of Singapore. Due to the presence of hard granite around Bright Hill Sta on, it was a challenge to install more than 1,500 secant bored piles, which were required for the Earth Retaining Stabilising Structures (ERSS) for the sta on before excava on work could commence. As the area is highly urbanised, the tunnels from Bright Hill Sta on towards its adjacent sta ons required tunnelling under an exis ng low-rise residen al building. To ensure safety, enhancement work was carried out to strengthen the building’s founda on system prior to tunnelling work.

TEL Lentor Sta on Entrance A.

Mayflower Sta on Mayflower Sta on is located in the mature Ang Mo Kio Estate and Kebun Baru Estate. The barrier-free entrances of Mayflower Sta on allow commuters, especially elderly residents, to access the sta on easily. The sta on will 12

THE SINGAPORE ENGINEER January 2020

Interior of TEL Bright Hill Sta on.

COVER STORY

Upper Thomson Sta on

THOMSON EAST COAST LINE STAGE 1

The Upper Thomson Sta on will serve the neighbouring residen al estates such as Soo Chow Estate, as well as developments such as Thomson Plaza, Church of the Holy Spirit, and various dining establishments.

The Thomson-East Coast Line Stage 1 (TEL1) comprises one depot at Mandai and three sta ons, including an interchange sta on at Woodlands that links to the North-South Line (NSL), providing commuters in Woodlands greater accessibility and shortening their travelling me. Woodlands Sta on is also equipped with a Civil Defence shelter.

As the sta on is located directly beneath the busy Upper Thomson Road and flanked by two rows of terrace houses, traﬃc diversions and canal diversion were implemented in phases, adjacent to Soo Chow Estate, to support the various stages of construc on. To reduce inconvenience to residents and commuters, a sec on of the linkway underneath Upper Thomson Road to Entrance B was constructed using the pipe roof and tunnel method. This involved using a retractable micro tunnel boring machine to install circular pipes horizontally to form the ERSS before mining excava on was carried out.

Woodlands North Sta on Woodlands North sta on is located between Woodlands Avenue 9 and Admiralty Road West. The sta on is about 270 m long, 48 m wide and 22 m below ground level. It has two entrances and comprises two levels concourse and pla orm. Students at Republic Polytechnic can enjoy be er connec vity with the opening of TEL1, with Entrance 1 leading directly to the school.

Woodlands Sta on

TEL Upper Thomson Sta on Entrance C.

Caldeco Sta on Caldeco Sta on will bring further convenience and connec vity to commuters working and residing in the Thomson Road Estate and Toa Payoh Rise Estates. This interchange with the CCL will also provide easier access to the Singapore Associa on of the Visually Handicapped, Lighthouse School, Mount Alvernia Hospital, St Joseph Ins tute Interna onal (SJII) and MacRitchie Reservoir. To avoid impac ng SJII, the mined tunnel construc on method was adopted as it would not require ground excava on. It is the largest mined tunnel ever constructed in Singapore in a mixed soil condi on. The sta on has been designed as a four-level underground sta on, and a total of 160,000 m3 of granite was removed using the electronic blas ng method.

Woodlands Sta on is located between Woodlands Square and Woodlands Avenue 2, and is an interchange sta on with the NSL, improving connec vity for Woodlands residents and commuters. The sta on is about 330 m long, 30 m wide and 24 m below ground level. It has four entrances and comprises two levels - concourse and pla orm.

Woodlands South Sta on Woodlands South Station is located along Woodlands Avenue 1, between the Woodlands Drive 16, Woodlands Drive 17 and Woodlands Avenue 1 junction. The station is about 206 m long, 24 m wide and 22 m below ground level and comprises two levels - concourse and platform. It has five entrances, one of which will open in tandem with the opening of the future Woodlands Health campus that is currently under development. The sta on serves students from neighbouring schools such as Woodgrove Secondary School, Singapore Sports School and Christchurch Secondary School.

Train frequency of TEL1 Passengers can look forward to new five-door, four-car trains for TEL. Trains will be running along TEL1 sta ons from Woodlands North to Woodlands South at frequencies of 10 minutes during peak hours and 15 minutes during oﬀ-peak hours, at the commencement of passenger service for TEL1. As ridership on TEL1 increases, the frequencies for both peak and oﬀ-peak hours will be reviewed and adjusted.

TEL Caldeco Sta on Entrance A.

All images by Land Transport Authority THE SINGAPORE ENGINEER January 2020

CONSTRUCTION PROSPECTS

SINGAPORE’S CONSTRUCTION DEMAND FOR

2020 EXPECTED TO REMAIN STRONG Built environment sector urged to look ahead, invest in digitalisa on and innova on-driven growth, and groom local talent to tackle the uptrend in larger and more complex projects. The Building and Construc on Authority (BCA) projects the total construc on demand (value of construc on contracts to be awarded) to remain strong in 2020 due to sustained public sector construc on demand. The total construc on demand is expected to range between SGD 28 billion and SGD 33 billion this year. Public sector construc on demand, which is expected to reach between SGD 17.5 billion and SGD 20.5 billion this year, will make up about 62% of the projected demand for this year. Public sector construc on demand is expected to be spurred by major infrastructure projects which are larger and more complex in scale, such as the Integrated Waste Management Facility, infrastructure works for Changi Airport Terminal 5, Jurong Region MRT Line and Cross Island MRT Line. Private sector construc on demand is projected to be between SGD 10.5 billion and SGD 12.5 billion this year, supported by projects such as redevelopment of en-bloc sale sites, recrea onal developments at Mandai Park, the Changi Airport new taxiway, and berth facili es at Jurong Port and Tanjong Pagar Terminal. The forecast for 2020 excludes any construc on contracts by the two Integrated Resorts (IRs), as the melines and phasing of the expansion projects for these two developments have yet to be confirmed. Last year’s total construc on demand expanded by 9.5% to reach SGD 33.4 billion, which is about SGD 1.4 billion higher than the upper bound of BCA’s 2019 forecast of SGD 27 billion to SGD 32 billion, mainly due to a stronger than expected increase in industrial construc on demand for petrochemical facili es despite the slowdown in the manufacturing sector. Total preliminary construcYear

Medium term forecast for 2021 to 2024 Construc on demand is expected to hold steady over the medium term. Demand is projected to reach between SGD 27 billion and SGD 34 billion per year for 2021 and 2022, and between SGD 28 billion and SGD 35 billion per year for 2023 and 2024. The public sector will con nue to lead demand and is expected to contribute SGD 16 billion to SGD 20 billion per year from 2021 to 2024, with building projects and civil engineering works each taking up about half of the demand. Besides public residen al developments, public sector construc on demand over the medium term will con nue to be supported by various mega infrastructure projects. BCA expects private sector construc on demand to stay at a moderate level in view of the likely con nued global economic uncertain es and the current overhang in the supply of private residen al housing units. Nonetheless, the planned expansion of the two Integrated Resorts could provide further upside to private sector demand, depending on their eventual construcon melines and phasing.

Construc on output Total nominal construc on output in 2020 is projected to increase to between SGD 30 billion and SGD 32 billion, from the es mated SGD 28 billion in 2019. The an cipated further pick-up in total construc on output in 2020 is supported by the improved construc on demand since 2018, following the slowdown in 2015 to 2017.

Construc on demand (Value of contracts awarded, S$billion)

Construc on Output (Value of cer fied progress payments, S$billion)

Public

Private

Total

2019 p

19.0

14.4

33.4

2020 f

17.5 – 20.5

10.5 – 12.5

28 – 33

30 – 32

11 – 14 per year

27 – 34 per year

12 – 15 per year

28 – 35 per year

2021 – 2022 f 2023 – 2024 f

16 – 20 per year

p: Preliminary f: forecast Construc on demand and Construc on output. 14

on demand last year for the public and private sectors was SGD 19 billion and SGD 14.4 billion, respec vely.

THE SINGAPORE ENGINEER January 2020

CONSTRUCTION PROSPECTS

Pressing on with the industry transformation efforts With the positive outlook in the medium term, Mr Zaqy Mohammed, Minister of State for National Development and Manpower also urged the industry to continue to invest in a skilled and competent workforce with a strong local core, in order to sustain business growth and the good progress in transformation that have already been made. Since the Construction Industry Transformation Map was launched in 2017, the industry has been using newer and more advanced technologies to improve construction processes and methods, and ultimately create new and better jobs for those working in the sector. For example, more projects are adopting Design for Manufacturing and Assembly (DfMA), where a substantial portion of work is now done in a controlled manufacturing environment before it is transported to site for assembly. The DfMA adoption rate by the industry shows an improvement from 22% in 2018 to about 30% in 2019, which is good progress towards the target of 40% by 2020. The public sector will continue to take the lead in adopting DfMA. In the case of HDB’s building projects, for example, 75% of all units launched in 2020 will adopt DfMA methods such as Prefabricated Pre-finished Volumetric Construction (PPVC) or the Advanced Precast Concrete System (APCS).

Prefabricated Prefinished Volumetric Construc on Prefabricated Prefinished Volumetric Construction (PPVC) refers to a construction method by which 3-dimensional modules are completed with internal finishes, fixtures and fittings in an off-site manufacturing facility before they are delivered and installed on-site. The key benefits of PPVC include: • Improved Productivity PPVC can potentially achieve productivity improvements of up to 40% in terms of manpower and time savings, depending on the complexity of the projects. • A Better Construction Environment As the bulk of the installation activities and manpower are moved off-site to a factory-controlled environment, it can minimise dust and noise pollution, and improve site safety. • Improved Quality Control Off-site fabrication can result in better quality of end products, through quality control in a factory-like environment.

Besides DfMA, Integrated Digital Delivery (IDD) has been identified as a key transformation area for the built environment sector. Those who implement IDD can expect to reap benefits such as productivity gains throughout the building life cycle, reduction of costs and waste by minimising reworks, and improving site safety. For instance, BHCC Construction aims to achieve 30% time savings during the design of a project by using a Virtual Reality collaboration system and 25% time savings by digitalising its management of site safety records. Similarly, the multi-disciplinary project team, including the builder, for the Tuas Port Maintenance Base, aims to achieve 20% time savings by using a cloud-based digital platform for managing defects and site safety during construction works. The team also expects to achieve a 20% productivity improvement in maintenance work by integrating data from the Building Information Model into the building management system when the building is completed. The transformation efforts have led to the redesign or creation of new and better jobs, such as ‘Digital Lead’ and ‘DfMA Production Manager’ within the sector. To support the growth in the sector’s transformation, BCA is working with industry partners on initiatives to attract more fresh graduates and mid-career personnel into the sector, as well as on a skills framework to chart out career progression pathways which will be launched later this year.

A 3-dimensional module, constructed using the PPVC method, being installed at The Tapestry in Tampines. Image by CDL and Woh Hup.

THE SINGAPORE ENGINEER January 2020

CONSTRUCTION PROSPECTS

Advanced Precast Concrete System Advanced Precast Concrete System (APCS) refers to a construc on method that adopts large precast concrete (PC) components and/or the use of mechanical connec on systems to join two or more PC components under the ‘3S’ principles of Standardisa on, Simplicity and Single Integrated elements. The key benefits of APCS include: • Ease of on-site assembly Simplified structural design and connections make it easier for precast concrete components to be

assembled on-site. • Improved produc vity Reduced need for concre ng work on-site can lead to produc vity improvements of up to 20% in terms of manpower and me savings. • Improved Quality Control Wider adop on of automa on and manufacturing precast concrete components in a controlled factory environment allow for greater precision and higher quality standards.

Some of the features of the APCS.

Quickest expansion in eurozone construc on ac vity The latest PMI data pointed to the fastest increase in Eurozone construc on ac vity for eight months in December. Growth was supported by another rise in new orders and a further workforce expansion. Similarly, input buying increased at a quicker rate and supplier delivery mes lengthened amidst elevated demand. Up from 50.6 in November, at 51.3 in December, the IHS Markit Eurozone Construc on PMI pointed to a faster expansion in construc on ac vity across the currency area. In fact, the latest rise was the quickest for eight months amidst accelerated growth in both Germany and France. Across the euro area’s three largest economies, only Italy registered a reduc on in construc on ac vity. At the sub-sector level, faster growth was primarily driven by home building, where the rate of ac vity expansion was the fastest since May. The rise in total ac vity was also supported by a frac onal increase in the commercial sub-sector. Meanwhile, work undertaken on infrastructure projects con nued to fall, with the rate of decline li le-changed from October and solid overall. A key factor behind the increase in total construc on ac vity was a further rise in new orders in the final month of 2019. Purchasing Managers’ Index (PMI) data are compiled by IHS Markit for more than 40 economies worldwide.

THE SINGAPORE ENGINEER January 2020

CONCRETE TECHNOLOGY

ENHANCING STANDARD TEST APPROACH TO BETTER REFLECT APPLICATION REQUIREMENTS by C T Tam, Department of Civil & Environmental Engineering, Na onal University of Singapore Standard test methods are intended for assessing conformity requirements. The type of test equipment and procedure are well defined for the intended purpose. The materials, rela ve propor ons and method of preparing the test specimens are clearly detailed. The test environment, eg temperature and rela ve humidity are specified, where needed. However, some, if not all of the above, may not be the actual values for prac cal applica ons on site, par cularly in concrete construc on. This presenta on provides selected examples of how the above factors may be adjusted in the standard test methods for be er correspondence to actual project requirements or a modified test procedure which leads to a be er outcome. These include the consistence in terms of degree of compactability (previously compac ng factor), passing ability of SCC in fresh concrete, the s ďŹ&#x20AC;ening mes of concrete (generally in terms of se ng mes) and the temperature issues of peak temperature (poten al DEF) and maximum temperature diďŹ&#x20AC;eren al (poten al early thermal cracking) in hardened concrete arising from heat of hydra on of cement in the cas ng of thick concrete sec ons that may take many hours of con nuous cas ng. The enhancing of selected standard test methods with appropriate modifica ons be er relates to the actual applica on requirements and is presented. INTRODUCTION Standard test methods are intended for assessing conformity requirements. The type of test equipment and procedure are well defined for the intended purpose. The materials, rela ve propor ons and method of preparing the test specimens are clearly detailed. The test environment, eg temperature and rela ve humidity are specified, where needed. However, some, if not all of the above, may not be the actual values for prac cal applica ons on site, par cularly in concrete construc on. The quan ta ve results o en are not directly applicable to the site requirements. In the execu on of concrete structures, the performance of concrete is the actual interest. The principle of performance tes ng should be the same as in conformity tes ng. However, modifica ons in the test details together with the use of the actual cons tuents and composi on of the specified concrete for the project are used to assess the resultant performance. The above factors may be adjusted in the standard test methods for be er correspondence to actual project requirements or modified test procedure which leads to a be er outcome. This presenta on provides some examples selected to illustrate how the standard test procedures and the measurements can be modified to achieve the outcome to be er reflect applica on requirements.

density of par ally compacted concrete with the density of fully compacted concrete. The former test adopted the apparatus shown in Figure 1 to provide the same volume and the new approach is based on the same mass of concrete. The volume of fresh concrete completely filling the top hopper is dropped into the lower hopper and then into the cylindrical mould. The mass of the par ally compacted volume of concrete is then compared to the mass of a fully compacted volume of the same concrete. The compac ng factor (CF) is based on the ra o of the par ally compacted mass to that of the fully compacted mass of the same volume. A larger value of CF represents a higher degree of compac on. In lieu of comparing by mass, an alternate method to determine CF is by the volumes of the same mass. The volume of the par ally compacted concrete in the cylinder mould is compared to the volume of the same mass of fresh concrete [3,4].

DEGREE OF COMPACTABILITY For low level of consistence, the compac on of fresh concrete is formerly assessed by the compac ng factor test to BS 1881: Part 103 [1] which is now replaced by the test on the degree of compactability to BS EN 123504 [2]. In both methods, the principle is to compare the

Figure 1: Compac ng factor test apparatus [1].

Figure 2: Device providing direct CF result [3]. THE SINGAPORE ENGINEER January 2020

CONCRETE TECHNOLOGY

A direct reading device based on the change in height of the mass of concrete a er being fully compacted provides a directly calibrated reading in CF (Figure 2) [3]. The BS EN method adopts the same approach as the alternate volumetric method. The container has a square cross-sec on (200 mm x 200 mm) and a height of 400 mm. The container is completely filled with fresh concrete and then compacted on a vibra ng table to reach full compac on. The change in height of the concrete within the container is determined by taking the average of four readings, one each at the mid-point of the four sides of the container. The ra o of the original height of the concrete to that of the compacted volume is defined as the degree of compactability (C0 to C4 classes). A larger value (C0 ≥ 1,46) indicates a lower level of compactability compared to the smallest value (C4 ≤ 1,04). This method diﬀers from all the other consistence test methods for which a larger value indicates a be er consistence, eg slump S1 10 to 40 mm and S5 ≥ 220 mm. The new approach requires a volume of concrete about 2.25 mes that of the previous method. By changing the container to a cylinder of 225 mm diameter by 200 mm in height, to provide approximately the same volume (0.016 m3), a similar device to that for CF can be designed to give readings calibrated as the value of the degree of compactability directly. It is proposed that the degree of compactability to be redefined as the height of the compacted volume to that of the full height of the container as shown in Table 1 whereby a larger value indicates higher compactability. Class

Degree of compactability tested in accordance with EN 12350-4

Proposed (to nearest 0.005)

≤ 1,46

≤ 0.685

1,45 to 1,26

0.690 to 0.795

1,25 to 1,11

0.800 to 0.900

1,10 to 1,04

0.905 to 0.960

≤ 1,04

≥ 0.960

Table 1: Compac on classes (Table 4, BS EN 206) [5].

The adop on of a cylindrical container of the same volume as that of the square sec on container in BS EN 12350-4 [2] together with the direct reading device enables the result to be obtained without the need of manual measurement. This is expected to reduce the measurement uncertainty and improve both repeatability and reproducibility of the test method. The main contribu on to uncertainty is the way the mould is filled which will aﬀect repeatability as well as reproducibility. Furthermore, by introducing a displacement transducer to measure the progressive increase in depth and plotng the changing values with me, the end-point can be further monitored. The final value and the me taken to reach the value may be displayed as a depth- me plot. In addi on to a be er defined final value, the me for this provides addi onal indica on of the ease of achieving full compac on. This test method is o en specified for concrete pavement construc on but may also be useful 18

THE SINGAPORE ENGINEER January 2020

with concretes for precast elements where consistence in terms of slump is either S1 or S2 (10 to 90 mm). The former CF test with an intermediate hopper provides a degree of modera ng the influence of the operator factor in filling the upper hopper. However, the need to obtain the mass of fully compacted concrete in refilling the cylinder may introduce varia on in the composi on of the concrete between the two mass determina ons. The volumetric method avoids this factor. The main contribu on to uncertainty is the way the mould is filled which may aﬀect repeatability as well as reproducibility. The proposed replacement of the rectangular container with a cylindrical mould minimises possible corner eﬀects when vibra ng the concrete to full compac on. The use of a direct indica ng device also removes the uncertain es in taking the four measurements in the BS EN 12350-4 [2] method.

PASSING ABILITY The passing ability of self-compac ng concrete (also known as self-consolida ng concrete) is assessed by BS EN 12350-12 [6] using the J-ring (Figure 3) or by ASTM C 1621 [7] with the J-ring but with a different method of repor ng the passing ability. The BS EN test result is reported as the J-ring step. This is defined as the difference between the height of the concrete at the centre of the J-ring and the average of four readings of the height of concrete located at two perpendicular diameters of the J-ring just outside the bars of the J-ring. The acceptance value of the J-ring step (PJ) for both narrow and wide gap configura ons of the J-ring is ≤ 10 mm as stated in BS EN 206 (Table 10) [5]. The values of repeatability as well as reproducibility in BS EN 12350-12 [6] are 4,6 mm and 7,8 mm, respec vely, for the narrow gap (41 mm). Hence, the uncertain es in the J-ring test results are very large for applica ons. Although BS EN 12350-12 [6] provides values of repeatability and reproducibility for J-ring flow spread (SFj in mm) and J-ring flow me (t500j in s) in the case of narrow gap J-ring, BS EN 206 [5] does not provide any guidance on the acceptance value for either SFj or t500j. ASTM C 1621 [7] is also based on the use of the same J-ring and the narrow as well as the wide gap and narrow gap configura ons of the J-ring. However, the result is reported in terms of the reduc on in the flow spread due to the presence of the J-ring. Difference between slump flow and J-ring flow

Blocking Assessment

0 to 25mm [0 to 1in.] > 25 to 50mm [> 1 to 2 in.] > 50mm [2 in.]

No visible blocking Minimal to no ceable blocking No ceable to extreme blocking

Table 2: Blocking Assessment (ASTM C1621, Table 1) [7].

This approach was reported in an earlier publica on [8] prior to ASTM 1621-06 [7] in terms of the ra o of J-ring flow to that of slump flow. This is defined as the Passing Ability Index (PAI) with the use of a modified ring diameter of 500 mm (P-ring) [8]. Subsequently, addi onal test results on the usefulness of the P-ring have also been published [9]. Site requirements relate to the size and spacing of steel

CONCRETE TECHNOLOGY

reinforcement bars. Their influence on the passing ability of SCC is related to the degree of blockage (simulated by the number and bar size in the P-ring) and the clear gap space for the passing ability of SCC. Both factors are simulated by the diameter of the bars and the bar spacing in the P-ring. Only limited combina ons are provided in the J-ring test [6]. Table 3 shows the clear gap space (spacing less diameter of bar) and blocking ra o (sum of the number of bar diameters divided by the circumference of the 500 mm diameter P-ring. The P-ring provides the flexibility to assess the combined eﬀect of actual site requirements which are not available in any of the current test methods. Table 3 shows the clear gap space (bar spacing less one diameter of bar) and blocking ra o (sum of the number of bar diameters divided by the circumference of the 500 mm diameter P-ring). Annex A shows the two types of P-ring, Type A with provision for 4 to 24 bars and type B with provision for 4 to 32 bars together with the poten al range of clear gap spacing and blocking ra o using 10 mm, 20 mm or 40 mm diameter bars. Test method J-ring

P-ring 24 bar loca ons

Example P-ring 24 bar loca onsc P-ring 16 bar loca onsd

Clear gap space (mm)

Blocking ra o (%)

narrow gap wide gap narrow gap wide gap 16 x 18mm 12 x 18mm 16 x 18mm 12 x 18mm dia. dia. dia. dia. 41 59 31 23 24 x 20mm 24 x 16mm 24 x 20mm 24 x 16mm dia. dia. dia. dia. 25a 33a 31 24 12 x 45mm 12 x 36mm 12 x 45mm 12 x 36mm dia. dia. dia. dia. 41 59 34b 28b b a values not matching values not matching J-ring J-ring Ra founda on: 40mm diameter bars at 100mm centres both ways 60 40 8 x 70mm dia. 8 x 70mm dia. 56

16 x 40mm dia. 12 x 40mm dia. 41c 58c e e preferred preferred c Type A P-ring, dType B P-ring (Annex A)

Table 3: Clear gap space and blocking ra o.

Similarly, the L-box test [10] provides the clear gap space of 59 mm with two numbers of 12 mm diameter bars, and three numbers of 12 mm diameter bars for a clear gap space of 41 mm. The width of the box is 200 mm, providing blocking ra os of 12% and 18%, respec vely. These are much less than the blocking ra os for the corresponding clear gap spaces in the J-ring [6], of 23% and 32%, respec vely. Table 3 shows that the P-ring does not provide configura ons to match both the clear gap space and the blocking ra o of the narrow gap or wide gap configura on of the J-ring [6] at the same me, but for either one of them only. The two clear gap spaces in the P-ring [7] correspond to the two clear gap spaces adopted in the L-box test [10] (established earlier than the J-ring test). However the P-ring [7] with 500 mm diameter and up to 24 equally spaced bars is able to provide a wider range of clear gap spaces and

blocking ra os that can be er simulate the configura on of reinforcement bars for the actual concrete element. For example, a typical ra founda on configura on consis ng of 40 mm diameter bars at 100 mm spacing with a clear gap space of 60 mm and blocking ra o of 40% is approximated with 8 x 70 diameter bars giving a clear gap space of 56 mm and blocking ra o of 36%. On the other hand, the J-ring with a wide gap has a clear gap space of 59 mm but a blocking ra o of only 23%. The blocking occurs at 300 mm for the J-ring [6] but at 500 mm for the P-ring [7] at which the flow is slower. Combined with the lower blocking ra o, the J-ring [6] provides a less cri cal assessment of the performance requirement. By repea ng the P-ring test over a period of me since batching and rela ng the flow diameter at different me periods to ini al slump flow as reference, the reduc on in the value of PAI enables assessment of the result of an unintended delay. For ini al slump flow of 550 mm (SF1) [5] and J-ring flow at a difference of 25 mm [7,] the ra o, PAI = 525/550 = 0.95. For ini al slump flow of 850 mm (SF3) [5], the same difference of 25 mm, the ra o, PAI = 825/850 = 0.97. When the difference becomes 50 mm [7], the corresponding PAI = 0.91 and 0.94 respec vely. Hence, the acceptance range of PAI for SF1 is 0.91 to 0.95 and for SF3, the range is 0.94 to 0.97. The reduc on of PAI is in the order of 0.03 to 0.04 which may be considered as their acceptable limit. The PAI approach is likely to be more sensi ve in the assessment of passing ability than ASTM C 1627 [7] and more so than BS EN 12350-12 [6]. The increase in the value of the J-ring flow me, t500j over a period of me using the P-ring compared to t500 of ini al slump flow, offers an addi onal indica on of the reduc on in passing ability. However, as the values of t500 as well as t500j are generally within a few seconds (similar in order as their repeatability and reproducibility [6]), they are not sufficiently sensi ve to assess differences in passing ability. Hence, they have not been included in the requirements for SCC under BS EN 2065. The site requirements for passing ability of SCC are be er assessed based on PAI using the P-rings.

SETTING TIMES OF CONCRETE Although the term ‘se ng mes of concrete’ is commonly used, in order to emphasise the diﬀerence between ‘se ng mes of concrete’ from ‘se ng mes of cement’, it is preferable to adopt the term ‘s ﬀening mes of concrete’ as in BS 5075 [11]. Unlike the se ng mes of cement using the Vicat needle apparatus in BS 196-3 [12], the se ng mes of concrete are based on the penetra on resistance of wet-sieved mortar from fresh concrete, originally (1957) using the Proctor needles for soil test as stated in the early edi on of ASTM C 403 [13]. Penetra on resistance defined as ini al and final se ng mes of concrete do not relate to any specific change in concrete proper es [13]. Ini al set is usually considered to indicate the me at which the concrete can no longer become monolithic with previously placed concrete and final set when hardening begins [13]. Ini al set is defined as me since adding water for the wetsieved mortar to reach penetra on resistance of 3.5 MPa. Site prac ce has taken this to be the me for which a ‘cold joint’ may result between the already placed fresh concrete and the new fresh concrete to be placed over it (even when THE SINGAPORE ENGINEER January 2020

CONCRETE TECHNOLOGY

vibrated with a poker vibrator). A truly cold joint will show up as a dark line in hardened concrete, eg at a construc on joint. However, unless the already placed concrete has fully hardened, such a line is o en not observed. The par ally set concrete is mixed by vibra ng with the poker vibrator at the interfacial zone of the already placed concrete and the newly placed concrete. Hence poten ally a weakened zone may have been created. However, there is as yet no test method to assess such a situa on when delay occurs even though at the job site this has occurred, eg in cas ng of deep sec ons such as pilecaps or ra founda ons. The 3.5 MPa penetra on resistance me has been adopted as the prac cal criterion to specify required retarda on me in the concrete by addi on of set-retarding admixtures. Although this approach has served site prac ce sa sfactorily, it does not provide a direct method of assessing the poten al cold joint forma on issues. A more ra onal approach is needed to explore the actual situa on and to provide guidance on the way to handle this ma er on site, eg a test method to indicate if the already placed concrete has reached a stage that it will lead to an unacceptable zone when new fresh concrete is placed over it, and the use of a vibrator to intermix the new fresh concrete with the already placed concrete. A study [14] on this issue was conducted by considering the delay in cas ng of new fresh concrete over a few hours including the me when the wet-sieved mortar has reached 3.5 MPa. A specially designed ver cal beam mould of 100 mm square sec on for cas ng the 400 mm length in two halves has been adopted (Figure 3) [14]. The upper 200 mm of concrete was placed with delayed me of up to 6 hours a er the placing of the concrete in the lower 200 mm beam mould. The beams were removed from their moulds a er 1 day and moisture-cured ll the age of tes ng under the third-point loading system for flexural strength (modulus of rupture) in accordance with ASTM C78 [15]. Preliminary results from an ini al study (Figure 4) [14] shows that when the interfacial zone is disturbed (by rodding into about 50 mm of concrete placed earlier), there is no clear line to indicate a cold joint. The flexural strength for an increasing period of me to place the second batch of concrete resulted in a gradual reduc on of flexural strength. This is likely to be contributed by the intermixing of the par ally set earlier placed concrete with the new batch of concrete placed over it as shown in Figure 3 [14]. The total period of me starts from the placing of the lower half of the beam to beyond the me when the wet sieved mortar of the same concrete is placed. The results show a more significant reduc on of the flexural strength when the interfacial zone is not disturbed (by rodding into the already placed concrete of not more than 50 mm in the test programme) compared to the case when no such disturbance is applied. This situa on may be the case for placing with SCC as no vibra on will be applied by simply allowing the new SCC to flow over the already placed concrete. Based on the results shown in Figure 4, the expected forma on of a weak cold joint with a sudden large drop in the flexural strength at the me when the wet-sieved mortar reached penetra on resistance of 3.5 MPa did not happen. It has not been established if cas ng is repeated to further periods of me ll the final se ng me of concrete at penetra on resistance of 27.4 MPa may lead to the case 20

THE SINGAPORE ENGINEER January 2020

Figure 3: Ver cal cas ng beam formwork [4].

Figure 4: Reduc on of flexural strength with me [14].

of a sudden large drop in the flexural strength. This may be expected if the earlier placed concrete has hardened to the extent that the surface cannot be easily broken by rodding. Historically, the se ng me test of ASTM C403 [13] was first carried out using the Proctor penetra on needles with a hand-held device in the applied load, by means of a spring of maximum capacity of 110 lbf (approx 50 kgf or 490 N) [16]. Modifica ons to the method of determining the applied force were later introduced using a pressure gauge or load cell. BS 5075 [11] adopted the use of a self-indicating pla orm scale to measure the applied force. With these modified methods of measuring the applied force, there is poten al to do so directly on the fresh concrete in lieu of its wet-sieved mortar. In the preliminary study [15] for the concrete studied, at the me when its wet-sieved mortar reached 3.5 MPa, the penetra on resistance of the concrete was about 10 MPa. Although this is for the specific concrete tested, it indicates that the alterna ve of directly conduc ng the penetra on resistance on concrete may be applied to the already placed fresh concrete on site. Un l a more detailed study is conducted to determine the criterion for acceptance, the equivalent penetra on resistance of concrete corresponding to that of its wet-sieved mortar at a penetra on resistance of

CONCRETE TECHNOLOGY

3.5 MPa may be applied on site prac ce. The specific penetra on resistance of the fresh concrete may be established by carrying out penetra on resistance on both the concrete and its wet-sieved mortar for each specific concrete for the project. There is poten al to develop a portable loading device for this purpose to assess the concrete on site to decide the penetra on resistance of the already in-place concrete, providing an indica on of the poten al cold joint forma on.

TEMPERATURE LIMITS ARISING FROM HEAT OF HYDRATION The heat of hydra on of cement leads to a rise in temperature which can be significant in thick sec ons. Typically, a thickness above 500 mm will result in a measurable temperature rise even with a low heat cement. When this occurs, at temperatures above 70° C, the poten al for delayed e ringite forma on (DEF) is expected. Un l the mid-1990s, this phenomenon was not generally recognised. On the other hand, early thermal cracking due to temperature difference between the warmer interior and the cooler surface zone of a thick sec on is well accepted. However the difference in temperature (o en referred to as temperature differen al) that may result in surface cracks is less appreciated. It is not only the temperature difference but also the degree of boundary restraint (restraint factor). The combined effect determines the poten al for early thermal cracking. A commonly specified value is 20° C without considera on of the actual thickness and boundary condi on of the structural element. BS 8110 Part 2 [17] clause 3.8.4 provides guidance on this topic. The following statements are of par cular significance in understanding the issues: • The resul ng expansion of the hot core, if excessive, can stretch the cooler surface zone to the extent that cracking occurs. • In prac ce, however, restraints result in differen al thermal strains which depend on the nature of the temperature distribu on, and the ra o of the ‘hot’ and ‘cold’ areas. • Experience has shown that by limi ng temperature differen al to 20° C in gravel aggregate concrete, cracking can be avoided. • This represents an equivalent restraint factor R of 0.36. Based on the above statements, a value of 20° C represents the most conserva ve specified value when other types of aggregates and restraint factors apply. Experience in Singapore with ra founda on up to 4000 mm thick and the use of granite aggregate has not shown any surface cracking for temperature differen al up to 40° C (equivalent restraint factor R of 0.25) by ensuring boundary restraints are limited to one or two sides of the panel being cast. Reduc on of the boundary restraints effect for a thin wall on thick base by adop ng the first li height of not more 1 m has minimised poten al cracking. In temperate climates, where placing temperatures are not above 20° C even in summer, the maximum temperature seldom reaches 70° C, and DEF is less an issue than early thermal cracking arising from temperature differenal. Hence, insula ng the external surface is a common

requirement. In tropical climates, it is more difficult to keep maximum temperature from reaching over 70° C than avoiding early thermal cracking, as placing temperature is generally above 30° C. Given the complex interplay between restraint factor and the resultant temperature distribu on within any part of different types of structural elements, the simplis c specifica on of a temperature differen al cannot ensure sa sfactory results, par cularly in the case of a large pour for a ra founda on, with con nuous placement of concrete over many hours. Even analy cal methods based on data from a ‘hot box’ test as conformity test for an adiaba c temperature test are inadequate, as it is difficult to include into the numerical model, the progressively changing element thickness over the long period of placing. The expected performance is best assessed by means of a mock-up simula ng the actual process of placement and the nature of the structural element (column, transfer beam/slab or ra founda on). For precast elements, the actual formwork may be used with only its cri cal zone, by appropriate adapta on, eg the cross beam of an elevated light rail system. In the case of a thick founda on ra 4500 mm thick with a panel size 20 m x 60 m, the total volume of concrete is 5,400 m3. Placing at the rate of 60 m3/h for each pump discharge point and using two such pumps, will take 45 hours. Adop ng the layering technique [18] of placement in nine layers of 500 mm, each layer takes 5 hours. This calls for at least 7 hours of set retarda on me based on ASTM C403 [13] penetra on resistance test needles specified. In any specific case, op misa on with different placing temperatures for groups of layers (outer zones and central zone) to minimise temperature differen al, using different types of cements or addi on of waterproofing admixture are possible alternate approaches that have been presented elsewhere [19]. A mock-up to assess the expected performance is adopted to verify if the temperature limits specified are achieved ahead of the actual placement on site. The mock-up is made up of a 2.5 m x 2.5 m sec on of the full thickness of the ra to represent a central area within the ra and insulated on the four sides with 100 mm thick polystyrene foam panel to simulate the effect of concrete surrounding the sec on. The advantage of the mock-up approach with actual performance data over analy cal methods is a full temperature history record of this representa ve volume of the ra , from the start of placing concrete to the final stage when the warmest interior part of the volume has cooled down to less than 20° C differenal with the average ambient temperature. Actual examples reported include the case of a 2800 mm ra in seven layers (Figure 5) [19] which reached a maximum temperature of 66° C for a high slag cement (PBFC to BS 146) [20] at 350 kg/m3 plus silica fume of 20 kg/m2. Another case of a concrete with a 3700 mm thick mock-up in nine layers (Figure 6) [21] recorded a maximum temperature of 64° C and maximum temperature differen al of 22° C with no insula on at the top surface of the mock-up (Figure 7) [21]. Subsequently for the project, several large volume placements (600 to 1100 m3) recorded maximum temperatures and maximum temperature differen als that were within ±3° C of those for the mock-up. These cases provided a confirma on of the usefulness of performance tes ng. THE SINGAPORE ENGINEER January 2020

CONCRETE TECHNOLOGY

Figure 5: Temperature history of 2800 mm thickness.

Figure 6: Schema c illustra on for a nine layer mock-up.

Type A: 6 per quarter circle For 4, 8,12 or 24 bars

Type B: 8 per quarter circle For 4, 8, 16 or 34 bars Figure 7: Temperature history of 3700 mm thickness.

P-ring of 500 mm diameter (circumference = 1571 mm) (Ring A - 24 bars, Ring B - 32 bars with bar diameters of 10 mm, 20 mm and 40 mm) Degrees

No. of bars Ring A/B

Centre to Centre (mm)

5 6 7.5 10 11.25 12 15 20 22.5 30 45 60

72 60 48 (4 x12) 36 (4 x 9) 32 (4 x 8) 30 (3 x 12) 24 (4 x 6) 18 ( 3 x 6) 16 (4 x 4) 12 (4 x 3) 8 (4 x 2)(8 x 3) 6 (3 x 2)

NA NA 32.73 43.64 49.09 52.36 65.45 87.27 98.19 130.92 196.38 261.83

10 mm NA NA 23 34 39 42 55 77 88 121 186 NA

Gap Space - mm 20 mm 40 mm NA NA NA NA 13 NA 24 NA 29 NA 32 NA 45 35 67 47 78 58 111 91 176 156 NA NA

NA: not applicable (out of range shown in criteria) Criteria: Centre to centre: Maximum 200 mm, 1571/200 = 7.85, select 8 bars x 4 = 32 bars, 11.25 degrees Minimum 40 mm, 1571/40 = 39.27, select 10 x 4 = 40 bars, 9 degrees Annex A: Type A and Type B P-rings. 22

THE SINGAPORE ENGINEER January 2020

10 mm NA NA 31 23 20 19 15 11 10 8 5 NA

Blocking ra o - % 20 mm 40 mm NA NA NA NA 61 NA 46 NA 41 81 38 76 31 61 23 46 20 41 16 31 10 20 NA NA

Gap space: not less than 30 mm and not more than 100 mm (out of range) Blocking ra o: not more than 50 % and not less than 15 % (out of range)

CONCRETE TECHNOLOGY

CONCLUDING REMARKS Conformity tests are necessary to ensure that the cons tuent materials for concrete and the proper es specified for the concrete meet the specifica on for the project. However, the test results of conformity tes ng, in most cases, do not provide adequate informa on for the requirements of the project. Suitable modifica ons to the procedure and measurements of performance directly related to the project provide be er assurance of achieving the intended design and the in-service performance of the concrete structures. Some examples of this approach are presented to illustrate how such modifica ons can provide be er assessment of the extent a requirement may be achieved.

ACKNOWLEDGEMENT The author gratefully acknowledges the contribu ons and support of co-authors, colleagues and former research staﬀ and students in the various projects which are quoted in the references from which the data and opinions are derived. REFERENCES [1] BS 1881: Part 103: 1993, Method for determina on of compac ng factor, Bri sh Standards Ins tu on, London (previously BS 1881: Part 2: 1970). [2] BS EN 12350-4: 2000 - Tes ng fresh concrete - Part 4: Degree of compactability, Bri sh Standards Ins tu on, London. [3] Tam C T, Compac ng factor: a new test, Concrete, 10, No. 5, May 1976, pp 27 and 30. [4] DD 90: 1983, Volumetric method for determina on of compacting factor of fresh concrete, Bri sh Standards Ins tu on, London.

[14] Tam C T, Zhao X Y and Wang N, Preliminary study on determining me to cold joint forma on in delayed cas ng of concrete, Proceedings 42nd Conference on Our World in Concrete & Structures, 24-25 August, 2017, pp 49-54. [15] ASTM C78/C78-18, Standard test method for flexural strength of concrete using simple beam with third-point loading, ASTM Interna onal, West Conshohocken, PA, USA. [16] Tam C T, The eﬀect of a lignin-based admixture on proper es of concrete, PhD Thesis, University of Calgary, Alberta, Canada, 1972, 192 pp. [17] BS 8110: Part 2: 1985, Structural use of concrete, Part 2. Code of prac ce for special circumstances, Bri sh Standards Insitu on, London. [18] Loo Y H, Paterson J S, Swaddiwudhipong S and Tam C T, Applica ons of the layering on large concrete pours, Magazine of Concrete Research, V47, 1995, pp 209-217. [19] Tam C T, Swaddiwudhipong S, Ho D W S and Seow S S, Strategy for cas ng of ra founda on in tropical climate, J IES, Singapore, V42, N6, 2002, pp 6-12. [20] BS 146: 1958, Portland blast-furnace cement, Bri sh Standards Ins tu on, London. [21] Tam C T, Innova ve approach for cas ng of thick founda on ra s - sandwich concept, Proceedings, Twin Coimbra Interna onal Conference, 17-19 June 2009, Coimbra, Portugal, 4th Concrete Future - Recent Advances in Concrete Technology & Concrete in Structures, CI Premier, 2009, pp CF-31 to CF-40. (This ar cle is based on a Keynote Paper authored by C T Tam, Department of Civil & Environmental Engineering, Na onal University of Singapore and presented at the 44th Conference on ‘Our World in Concrete & Structures’ held in Singapore, from 29 to 30 August 2019. The conference was organised by CI-Premier Pte Ltd)

[5] BS EN 206: 2013 + A1: 2016, Concrete - Specifica on, performance, produc on and conformity, Bri sh Standards Ins tu on, London. [6] BS EN 12350-12: 2010, Tes ng fresh concrete - Part 12: Self-compac ng concrete - J-ring test, Bri sh Standards Ins tu on, London. [7] ASTM C1621/C1621M - 17, Standard test method for passing ability of self-consolida ng concrete by J-ring, ASTM Interna onal, West Conshohocken, PA, USA. [8] Tam C T, Sheinn A M M, Ong K C G and Chay C Y, Modified J-ring for assessing passing ability of SCC, SCC 2005, Chicago, 31st Oct - 2nd Nov 2005, Session D-3-2, (also Proceedings of First North American Conference on the Design and Use of Self-consolida ng Concrete, Chicago, USA, Nov 2002). [9] Chan K D, Ong K C G and Tam C T, Passing ability of SCC - Improved method based on the P-ring, Proceedings of 35th ‘Coral’ Anniversary Conference on Our World in Concrete and Structures, ‘Challenge of the Low Carbon Age’, CI-Premier, 26-27 August 2010, Singapore, pp 25-27. [10] BS EN 12350-10: 2010, Tes ng fresh concrete - Part 10: Self-compac ng concrete - L-box test, Bri sh Standards Insitu on, London. [11] BS 5075: Part 1: 1982, Specifica on for accelera ng and retarding water reducing admixtures, Bri sh Standards Insitu ion, London. [12] BS EN 196-3: 2016, Methods of tes ng cement - Part 3: Determina on of se ng mes and soundness, Bri sh Standards Ins tu on, London. [13] ASTM C403/C403M - 16, Standard test method for me of se ng of concrete mixtures by penetra on resistance, ASTM Interna onal, West Conshohocken, PA, USA.

Hybrid polymer concrete paving In 2017, the ASCE (American Society of Civil Engineers) gave America’s bridges a Safety and Condi on ra ng of C+. Bridges are built to last approximately 50 years. The average age of US bridges is now 42. Of the approximate 610,000 rural and urban bridges in the US, more than 24% are considered func onally obsolete or structurally deficient. The stresses affec ng the naon’s bridges will only increase as traffic volumes rise and the demand for heavier semi freight loads grows. One solu on to the problem involves the use of an advanced hybrid polymer concrete overlay that creates a highly durable, flexible and waterproof surface. The overlay epoxy quickly develops high tensile strength that seals, protects and extends the life of bridge decks in both new construc on and refurbishment work. The epoxy binder is applied evenly to the bridge deck surface. Aggregate is then immediately applied over the binder, increasing the texture depth of the pavement and providing a long-las ng seal to protect the bridge deck from the effects of traffic and harsh weather condi ons.

THE SINGAPORE ENGINEER January 2020

CONSTRUCTION LAW

PAYMENT CLAIMS

ENTITLEMENTS AND LIMITATIONS by Jimmy Yap, Accredited Adjudicator (Partner) and Daphne Tan (Associate), CNPLaw LLP, Singapore In 2019, the Court of Appeal considered whether a contractor had the right to apply for adjudica on under the Building and Construc on Industry Security of Payment Act (“SOP Act”). The construc on contract in that case incorporated, with some modifica ons, the standard terms of the Singapore Ins tute of Architects’ Ar cles and Condi ons of Building Contract (Measurement Contract) (“SIA Form Contract”), and the claimant-contractor served the relevant payment claims on the respondentdeveloper a er the architect had already issued a final cer ficate in accordance with the terms of the construc on contract. The respondent-developer argued that these payment claims were invalid as they were not accompanied by an architect’s cer ficate, as required under the SIA Form Contract. The Court of Appeal ruled in favour of the respondent-developer. This ar cle provides a brief summary of the decision and key takeaway points for those in the construc on industry. The case before the High Court In Yau Lee Construc on (Singapore) Pte Ltd v Far East Square Pte Ltd [2018] SGHC 261 (“Yau Lee”), the developer argued that the adjudica on determina on ought to be set aside on the basis that the adjudicator had no jurisdic on to determine the adjudica on applica on [1]. The developer argued this to be the case as the payment claims submi ed by the contractor and which formed the basis of the claimant’s adjudica on applica on were submi ed a er the architect had already issued a final cer ficate. The developer argued that as a consequence of having been submi ed a er the architect’s issuance of the final cer ficate, the payment claims fell outside the scope of the SOP Act [2]. The High Court ruled in favour of the contractor on the basis of the duty to speak espoused in Audi Construc on Pte Ltd v Kian Hiap Construc on Pte Ltd [2018] 1 SLR 317 (“Audi Construc on”) [3]. The High Court accepted the contractor’s argument that the developer was estopped from objec ng to the validity of the payment claim in ques on as the developer failed to serve a payment response in rela on thereto [4].

The case before the Court of Appeal The developer appealed, and in the case of Far East Square Pte Ltd v Yau Lee Construction (Singapore) Pte Ltd [2019] 2 SLR 189 (“Far East”), the Court of Appeal considered whether the developer had a duty to speak in respect of the payment claims in question. The Court of Appeal answered this question in the negative. The Court of Appeal interpreted the relevant clauses of the SIA Form Contract and held that the SIA Form Contract imposed as a condition precedent to 24

THE SINGAPORE ENGINEER January 2020

a contractor’s right to payment, an architect’s certification of the value of the works that have been done [5]. Having held that the said condition precedent had not been and, indeed, could not have been fulfilled in relation to the payment claims in question, the Court of Appeal held that the duty to speak referred to in Audi Construction was not engaged. The Court of Appeal held that the said duty to speak arose, in respect of objections to the jurisdiction of an adjudicator in an adjudication under the SOP Act, only in relation to payment claims which fell within the scope of the SOP Act, and that the payment claims in question did not.

The ra onale underscoring the Court of Appeal’s decision The SIA Form Contract does not expressly state that the issuance of an architect’s cer ficate is a condi on precedent to a contractor’s en tlement to payment and/or to apply for adjudica on under the SOP Act. However, the Court of Appeal’s finding was well-reasoned on the following bases: • Whilst sec on 5 of the SOP Act provides that any person that has carried out any construc on work under a contract is en tled to a progress payment, sec on 6(a) provides that the quantum of the said en tlement “shall” be calculated “in accordance with the terms of the contract”. In other words, sec on 5 s pulates the circumstances in which a contractor is en tled to a progress payment (namely, when the contractor has carried out any construc on work or has supplied any goods or services under a contract), whilst sec on 6 prescribes that the said en tlement must be quan -

CONSTRUCTION LAW

fied in accordance with the terms of the contract, and if the contract is silent in rela on thereto, sec on 6(b) provides that the said en tlement is to be quan fied on the basis of the value of the work done or goods or services supplied. • Clause 31(2)(a) of the SIA Form Contract states that the basis of a contractor’s payment claim shall comply with the valua on rules set out in sub-clause (4), which subclause goes on to prescribe the method with which the architect is to value the works. Simply put, this clause cons tutes the “terms of the contract” referred to in sec on 6 of the SOP Act. • Clause 31(2)(a) of the SIA Form Contract also requires the contractor to serve a copy of its payment claim on the architect. The Court of Appeal highlighted that the wording of clause 31(2)(a) en tled a contractor to serve a payment claim on the developer, but required (by using the word “shall”) the contractor to forward a copy of the same to the architect. • Clause 31(3) of the SIA Form Contract requires the architect to issue an interim cer ficate within 14 days a er the architect’s receipt of the payment claim. Put another way and read with clause 31(2)(a), the mandatory wordings in the SIA Form Contract in rela on to a contractor’s forwarding of a copy of its payment claim to the architect, together with the architect’s issuance of an interim cer ficate within 14 days of its receipt thereof, rendered the issuance of an architect’s cer ficate in rela on to a payment claim a condi on precedent to the claimant’s en tlement to the said payment claim. In Far East, it was no longer possible for the architect to issue such a cer ficate. This was because the architect had, in accordance with the SIA Form Contract, issued a final cer ficate and therefore lost the ability to issue any further cer ficates therea er. As such, in Far East, the requirement prescribed by clause 31(2) (a) of the SIA Form Contract was no longer capable of being fulfilled, with the consequence that the contractor’s en tlement to progress payments under sec on 5 of the SOP Act could no longer be quan fied, as mandatorily required by secon 6 of the SOP Act, in accordance with the “terms of the contract”. As a result, since the contractor could not establish an en tlement to payment, the Court of Appeal held that the contractor was not en tled to apply for adjudica on under the SOP Act and that the respondent was accordingly not under the duty to speak specifically referred to in Audi Construc on.

Takeaways from the Court of Appeal’s decision for construc on contracts incorpora ng the SIA Form Contract Contractors should note that a construc on contract that incorporates the terms of the SIA Form Contract has the eﬀect of precluding them from being en tled to payment under a payment claim unless and un l the project architect has issued an interim cer ficate in rela on to the said payment claim. As a contractor, you can go on to

accept the architect’s cer fica on and interim cer ficate or choose to dispute the same (by, for example, filing for adjudica on under the SOP Act). Further, you should also note that under the SIA Form Contract, the architect’s final cer ficate is just that - final - and that the architect cannot cer fy any payment claims you issue therea er because the SIA Form Contract does not allow the architect to do so. Any such cer fica on will no doubt be challenged by your employer, and in the light of the Court of Appeal’s decision in Far East, such a cer ficate is likely to be meaningless in any event. You may therefore wish to nego ate for an amendment to your construc on contract for more flexibility, by, for example, expressly providing for an alterna ve mechanism under which you can claim payment even a er a final cer ficate has been issued, if you are of the view that such an alterna ve mechanism is necessary for your scope of work. Alternatively, if you have already entered into a construction contract which incorporates the SIA Form Contract and which does not provide for such an alternative mechanism, you may wish to explore whether it is viable for you to bring your claim against your employer before the courts or, if there is an arbitration agreement (as is the case in the SIA Form Contract), commencing arbitration with your employer on other bases, eg a common-law entitlement to recover a reasonable sum for work done (also known as quantum meruit).

Key takeaways from the Court of Appeal’s decision for other construc on contracts The factual matrix of the case in Far East precluded the contractor in that case from having recourse to adjudication under the SOP Act. The outcome of the case is a lesson learnt on the part of the contractor. Simply put, a contractor that is not entitled to receive payment under their construction contract is similarly not entitled to apply for an adjudication of its payment claim under the SOP Act. As a contractor, you must take note of the terms of your entitlement to payment under the construction contract and act in accordance therewith in order to establish a right to be paid for the work you have done. If, as a contractor, you have taken the posi on that an outstanding amount is due to you for work done under a construc on contract which incorporates the terms of the SIA Form Contract a er the project architect has issued a final cer ficate, you will not be able to apply for adjudica on under the SOP Act and will have to commence arbitra on instead. In other words, where, as a contractor, your construc on contract imposes upon you addi onal requirements or condi ons precedent to your en tlement to payment, ensure that you comply with these strictly. If you are unable to do so for reasons out of your control, try nego a ng with your employer for a waiver of your compliance with that requirement or condi on immediately in wri ng. THE SINGAPORE ENGINEER January 2020

CONSTRUCTION LAW

Conclusion

References

To conclude, Far East makes clear that a claimant must first address the issue that was presented to the Court of Appeal in that case - namely, that it is contractually en tled to payment - in order to establish that its payment claim falls within the ambit of the SOP Act and that it is en tled to commence adjudica on. Then, and only then, can a puta ve respondent be said to be under the duty to speak espoused in Audi Construc on such that it is estopped from advancing any objec ons not stated in its payment response.

[1] Yau Lee at [11].

Accordingly, contractors should not take for granted their en tlement to commence adjudica on by virtue of their employer’s silence and failure to provide a payment response. As a contractor, review your construc on contracts thoroughly and ascertain comprehensively the terms that you have to comply with and the condi ons that must be fulfilled in order for you to be contractually en tled to payment. This will help you ensure that your adjudica on applica ons are not defeated on the jurisdic onal basis that was successfully presented by the respondents in Far East. Employers should do likewise to avoid incurring, unnecessarily, the costs of defending against invalid adjudica on applica ons on the substanve merits.

[2] Yau Lee at [12]. [3] In Audi Construc on, the Court of Appeal held that the SOP Act’s prescrip on of a mandatory requirement that an employer file a payment response in response to a payment claim filed by the contractor imposed upon the employer an aﬃrma ve duty to speak as to any objec ons the employer might have to the contractor’s payment claim. Audi Construc on stands for the proposi on that an employer that neglects to do so is estopped from raising any objec on not contained in its payment response. A more detailed analysis of Audi Construc on is provided in Subramanian Pillai, Daphne Tan, and Leonard Chua: “An Overview of the Recent Amendments to the Building and Construc on Industry Security of Payment Act”, CNPUpdate, 19 June 2019. h ps://www.cnplaw.com/an-overview-of-therecent-amendments-to-the-building-and-construc on-industrysecurity-of-payment-act/. [4] Yau Lee at [28] and [34] to [39]. [5] Far East at [35] and [39]. Disclaimer: This ar cle is provided as general informa on and should not be relied upon as legal advice. (More informa on rela ng to this ar cle and the subject ma er discussed may be obtained by emailing jyap@cnplaw.com or dtan@cnplaw.com)

Value of UK construc on disputes falls below global average The average value of construc on disputes in the UK fell by a massive 47% in 2018, according to Arcadis. The value of disputes averaged just USD 17.9 million in 2018, which was well below the global average of USD 33 million, marking a significant decrease over the last six years. The findings were revealed in the ‘Arcadis Global Construc on Disputes Report 2019: Laying the Founda on for Success’. The report provides insight into the causes, dura on and value of construc on disputes, while highligh ng the best ways to avoid, mi gate and resolve them. According to the report, the UK also remained the jurisdic on with the shortest average length of me to solve a dispute -12.8 months. However, this was up approximately 28% on the previous year and was consistent with the global trend which shows disputes are taking longer on average to resolve. The research highlights that failing to administer the contract correctly or human factors can o en be the primary cause of disputes. As mega-projects con nue to expand around the globe, inevitably the procurement, contracts and construc on of the projects themselves become more complex. Projects are ul mately at risk of failing when uncertainty and expecta ons are inadequately managed.

THE SINGAPORE ENGINEER January 2020

However, as the industry seeks to be er understand and address the impact of human factors in disputes, it is hoped that early dispute resoluon techniques - such as dispute avoidance - will become increasingly common. Currently in the UK, most disputes are resolved a er they have crystallised, rather than par es seeking to avoid or mi gate poten al dispute situa ons as they arise. While it is encouraging that nego a on remains the preferred method of resolu on, research respondents said that the number one factor which could have the biggest impact in avoiding disputes at all would be ‘a willingness to compromise in the dispute’. “In some cases, it could be argued construc on contracts are simply too complex for administrators to understand, and be er training for everyone involved would go some way towards avoiding disputes as they arise. However, our results show the UK to be a world leader in eﬀec ve avoidance and mi ga on strategies, and as we con nue to transion towards greater use of digital technologies like BIM and 4-, 5- or 6D modelling, we are likely to see an improvement in risk alloca on much earlier on in the process. This could help all par es to collabora vely resolve any diﬃcul es before cost and me pressures start to escalate”, said Gary Ki , Head of UK Contract Solu ons at Arcadis.

THE STRUCTURAL AWARDS 2019

WINNING PROJECTS REPRESENT SUPREME GLOBAL ENGINEERING FEATS The Ins tu on of Structural Engineers (IStructE) announced the winners of The Structural Awards 2019 during a gli ering black- e event held at The Brewery, London, UK, in November last year. The winners were chosen from a shortlist of 49 pioneering global projects in 12 categories, celebra ng the ingenuity and exper se of the engineers behind them. A diverse range of structures was recognised across 12 categories. The entries underlined the crea vity of Structural Engineers and their ability to harness digital tools to design structurally eﬃcient buildings. The winning projects showcase cu ng-edge examples of innova ve engineering solu ons. The New To enham Hotspur Stadium, UK, received the 2019 Supreme Award for Structural Engineering Excellence. The coveted accolade is presented to the year’s finest example of Structural Engineering design. The judging panel, made up of a dis nguished group of industry experts, were unanimous in their view about the cable-net roof structure, which is a vital feature of this redevelopment project. The judges were impressed by the ingenuity shown by the structural designers in dealing with very challenging constraints and requirements. They added that the a en on to detail throughout is exemplary and is an excellent showcase for the structural engineer’s art. Structural innova on is evident in the sliding pitch, vast open concourses and an almost impossibly light roof. They felt that the sheer elegance of structural form, lighttouch use of resource, and outstanding detailing evident in key connec ons all pointed to design worthy of the 2019 Supreme Award.

The Structural Awards The Structural Awards are the world’s foremost celebraon of Structural Engineers as innova ve, crea ve design professionals and the guardians of public safety. For over 50 years, the Structural Awards have showcased the world’s most cu ng-edge engineering achievements. Past winners include iconic structures such as the Sydney Opera House, the Pompidou Centre and the Severn Bridge. All entries are reviewed by a panel of world renowned judges who are truly passionate about structural engineers’ contribu on to society as design professionals.

The Ins tu on of Structural Engineers The Ins u on of Structural Engineers (IStructE) is the world’s largest membership organisa on dedicated to Structural Engineering. IStructE leads and supports the development of Structural Engineering worldwide, in order to secure a safe and resilient built environment for all.

Chair of the judges, Professor Tim Ibell, commented, “Many congratula ons to all the winners and thanks to those who entered the awards. Each year, the quality of the projects keeps ge ng be er. This year, we saw some excellent examples of the exploita on of digital tools, geometry, choice of materials to improve and enhance structural behaviour and, most importantly, the carbon footprint”. He con nued, “Keeping in mind the current climate crisis; we must pledge to build structures which are kind to the environment. Reuse and refurbishment should be our adopted mantra. With the net zero carbon target in sight, we wholeheartedly support the Structural Engineer’s Declara on which encourages companies and us to change the way we work”. Now in its 52nd year, these pres gious awards celebrate the world’s most outstanding achievements and demonstrate the diversity of structural engineering, recognising excellence, crea vity and innova on, as well as sustainability, economic viability and value for money.

New To enham Hotspur Stadium, London, UK, Winner of the 2019 Supreme Award for Structural Excellence and the Award for Long Span Structures. Engineer: BuroHappold Engineering and Schlaich Bergermann Partner. Images by Hu on+Crow. THE SINGAPORE ENGINEER January 2020

THE STRUCTURAL AWARDS 2019

AWARD WINNING PROJECTS THE AWARD FOR LONG SPAN STRUCTURES Project: New To enham Hotspur Stadium, London, UK. Engineer: BuroHappold Engineering and Schlaich Bergermann Partner.

weight looped cable structure with an outer compression ring and two inner tension rings. The new mul -purpose stadium can seat 62,062 and will also host NFL games. Judges’ comment “This is an impressive stadium containing many drama c long span solu ons. The judges were impressed by the ingenuity shown by the structural designers in dealing with very challenging constraints and project requirements. The roof is a complex lightweight cable-net structure with an external compression ring and two internal tension rings. Horizontal loads and uneven loading condi ons are carried by geometrical s ﬀness only, thus op mising the primary structural members to a minimum size and achieving the desired lightness and transparency.

New To enham Hotspur Stadium, London, UK.

Project descrip on The cable-net roof structure is a key feature of this stadium redevelopment project. The final design is a light-

THE AWARD FOR TALL OR SLENDER STRUCTURES Project: CITIC Tower, Beijing, China. Engineer: Arup.

In addi on to the roof, the concrete stands also incorporate long spans for various reasons, including the accommoda on of the en re retractable pitch which slides back under the south stand when the stadium is in use for concerts and other events. The a en on to detail throughout is exemplary and is an excellent showcase for the structural engineer’s art”.

lenges to its structural engineers. They developed a design that combines well-known systems in an intelligent way, including an innova ve means of construc on”.

Project descrip on With a height of 528 m, this 108-storey tower is possibly the world’s tallest building constructed in a high seismic zone. A gently rising and curving profile gives the building a contemporary and elegant expression, accommodates more prime-floor spaces at the top levels and provides structural stability at the base. Judges’ comment “The judges were impressed with the mul -faceted structural design for an extremely tall and slender building in a high seismic zone. Using parametric design , hundreds of poten al solu ons were explored. The tower employs a mul ple lateral load resis ng system with a central concrete core and a perimeter mega-frame. The external mega-frame is built from concrete-filled steel box sec ons. Belt trusses at mechanical/refuge floors provide further stability. An intelligent construc on approach was developed using an integrated pla orm - a steel frame structure set on the top of the concrete core that was jacked up as work progressed. This mul -level construc on pla orm saved me and cost of conven onal cranes and provided a work-place in the sky. With its challenging form (widening towards the top), challenging loca on (high seismic condi ons) and extreme height (528 m), this tall tower presented mul ple chal28

THE SINGAPORE ENGINEER January 2020

CITIC Tower, Beijing, China. Image by Wentao.

THE STRUCTURAL AWARDS 2019

THE AWARD FOR VEHICLE BRIDGES Project: Kienlesberg Bridge, Ulm, Germany. Engineer: KREBS + KIEFER.

The 270 m-long crossing has a unique undula ng appearance. The structure was prefabricated in segments which were welded on site and launched over live rail traﬃc. Judges’ comment “This is a highly sympathe c new pedestrian, cyclist, and tram bridge. The structure reflects the enormous benefits of interdisciplinary work between engineers and architects. The sinuous silhoue e is derived from the natural distribu on of bending moments, and op mised for a longitudinal launching process. At the same me, it is an architectural homage to the nearby 110-year-old wrought-iron Neutor Bridge. The judges admired how the graceful, economic, and eﬃcient appearance belies the complexity of the site and irregularity of the support condi ons.

Kienlesberg Bridge, Ulm, Germany. Image by Knight Architects.

Project descrip on Kienlesberg Bridge is a combined tram, cyclist, and pedestrian bridge crossing a busy railway hub.

THE AWARD FOR PEDESTRIAN BRIDGES Project: Tanxishan Glass Landscape Pedestrian Bridge, Zibo, China. Engineer: Tongji Architectural Design (Group) Co Ltd.

Notably, the structure of the main crossing was prefabricated in short segments, assembled on an elevated scaﬀolding at the south abutment and truss adjacent. This three-stage launch procedure was complicated by the curved east sec on but well managed by the engineers”.

and challenging access. The team used 3D laser scanning technology to model the topography and integrated it into the design model.

Project descrip on Spanning two cliﬀs on the top of Tanxi Mountain, this curved girder bridge is supported by a single-side cable arch system. Due to the harsh and narrow construc on space on the top of the mountain, an innova ve construc on method was required.

Considerable a en on to feasible and eﬃcient construcon led to an innova ve two stage rota on of girder and arch construc on sequence which reduced the temporary works requirements. To achieve this, key hinge joints that performed for both the permanent and staged temporary construc on cases were developed and a special climbing construc on device was designed for construc on of the curved structure.

Judges’ comment “The form of the bridge has created a landmark for the area with its long spanning elegant profile both in the sweeping horizontally curved glass desk and its ver cally curved inclined arched support.

Eﬃciency in form was also considered by load balancing arch and deck allowing for a single-sided cable solu on. The final bridge solu on is a sophis cated resolu on of complex Structural Engineering considera ons realised in an elegant form”.

Connected by cables, together they generate a sculptural form in this mountainous region. It is clearly man-made yet compliments its surrounding natural environment. The structural engineering ambi on, execu on of engineering judgement, thoroughness of design and delivery clearly contributed to the success of this bridge. The engineer’s role as part of a team of close collaborators from many diﬀerent design and construc on professions is evident in the finished bridge. The bridge is flanked by drama c mountainous terrain that challenged the team to design for complex topography in a remote site with narrow construc on space

Tanxishan Glass Landscape Pedestrian Bridge, Zibo, China. THE SINGAPORE ENGINEER January 2020

THE STRUCTURAL AWARDS 2019

THE AWARD FOR SMALL PROJECTS (of under GBP 3 million) Project: Millet Vinegar Museum, Zibo, China. Engineer: Light Earth Designs. Project descrip on The entrance hall of the museum is a newly built dome with a height of 9.1 m and a diameter of 12 m. The construc on scheme combined use of a local brick kiln with the latest masonry technology.

Each layer of bricks was carefully planned and sequenced to avoid formwork. Subtle rota on of the various courses of bricks achieved the decora ve texture of the arched openings. The result is a splendid example of a project made both conceptually and aesthe cal beau ful by an engineer’s skilled and sympathe c guiding hand”.

Judges’ comment “The Millet Vinegar Museum’s beau ful brick dome stands 147 brick courses high and punctured by three large arched openings. While in some ways this may be seen as a tradi onal structure, the engineers’ approach to the design was evidently me culous and bold. The dome is in the highly seismic Shangdong Province area of China. The engineers were clearly resistant to the tempta on to betray the pure brick form with steel or other duc le fixings. Instead, they relied on their confidence, borne of accurate and considered analysis and op misa on of the dome shape, to resist lateral forces.

THE AWARD FOR STRUCTURES IN EXTREME CONDITIONS Project: Tūranga, Christchurch, New Zealand. Engineer: Lewis Bradford Consul ng Engineers. Project descrip on A new central library built following the devasta ng 2010-2011 earthquakes in Christchurch. Tūranga was constructed to very stringent seismic performance criteria and features state-of-art seismic resis ng systems. Judges’ comment “The concept for this five-storey, 10,000 m2 library was inspired by the 2010-2011 earthquakes that aﬀected Christchurch, New Zealand, where the majority of buildings remained safe, but a great number were uneconomic to repair and required demoli on.

Millet Vinegar Museum, Zibo, China.

able to ‘rock’ due to their connec on to the founda ons and to adjacent components being made with replaceable shock-absorbing devices. They work in conjunc on with a perimeter steel moment resis ng frame which also has rocking base connec ons. The engineers were instrumental in encouraging plant, that would have been positioned in a basement, to be placed on the roof, allowing the proposed basement to be removed from the scheme. This enables the building to be constructed off a shallow gravel layer, avoiding both the expensive basement and costly piled foundations. A great example of how structural engineers can make such a crucial diﬀerence to a building, this is in every sense - a building that rocks!”

Tūranga’s hidden beauty lies in its level of seismic resilience, such that a er a serious seismic event, the shock absorbing systems could be readily replaced and the building would be re-usable. The massive concrete core walls, some weighing around 140 tonnes, were cast flat on site and then ‘ lted up’. They provide stability to the building and in a seismic event are 30

THE SINGAPORE ENGINEER January 2020

Tūranga, Christchurch, New Zealand. Image by Adam Mork.

THE STRUCTURAL AWARDS 2019

THE AWARD FOR STRUCTURAL HERITAGE Project: Newquay Harper Bridge, Newquay, UK. Engineer: Free4m.

‘Harper Bridge’ designs remaining in the UK and an important piece of Bri sh engineering history. A method was devised by the engineers to carry out the restora on without support works, allowing the bridge to remain open throughout and crea ng a considerable cost-saving for their client. Judges’ comment “The structural engineers carried out considerable research into the history of the bridge and even consulted with the original designer’s grandson who himself researched the history of Harper bridges. The scheme recognised that only the suspension bridge hangers were in need of replacement and researched the original details thus returning it as close as was feasible to its original design. In this way, the suspension cables were saved, which resulted not only in a highly sustainable solution but saved significant cost and areas of the original structure.

Newquay Harper Bridge, Newquay, UK. Image by Free4m.

Project descrip on Restora on works to this footbridge returned it to its original structural design, preserving one of the few

The judges were par cularly impressed by this minimalist approach which was underpinned by detailed research and sound engineering judgement”.

THE AWARD FOR STRUCTURAL TRANSFORMATION

This was achieved through an elegant roof structure consis ng of a primary ed arch at the centre of the new deformed roof plates, which in turn supports secondary trusses following the curved geometry of the roofs and from which the new floor is suspended.

Project: Coal Drops Yard, London, UK. Engineer: Arup. Project descrip on Two Victorian train sheds and arches were transformed to create a retail centre and focal point for London’s King’s Cross development. The project combined Victorian engineering with contemporary interven ons that enhance the historic architecture and features a striking new roof and floa ng floor. Judges’ comment “This transforma on project required intricate structural design solu ons to ensure faithful delivery of the fine architectural aesthe cs.

The primary truss has a moment-resis ng V-notch at its apex in order to faithfully maintain the aesthe c of the ‘kissing’ roofs. Torsion and deflec on of the curved trusses were carefully calculated and systema cally monitored throughout the construc on process in order to maintain deforma on of the suspended floor within predetermined acceptable limits. The design team have skillfully combined sensi ve renova on of neglected heritage structures with complex extensions to form a seamless and integrated composi on”.

Restora on and renova on of the existing brick, mber and cast-iron structures was carried out a er individual assessment of their structural viability, retaining as much of the original materials as possible. The success of the development relied upon the crea on of a suspended floor linking the East and West Coal Drop buildings, thereby crea ng a unified public area protected by the peeledback slate roofs complemented by infill glazing to the lenses created by the new roof geometry.

Coal Drops Yard, London, UK. Image by Argent / John Sturrock. THE SINGAPORE ENGINEER January 2020

THE STRUCTURAL AWARDS 2019

THE AWARD FOR CONSTRUCTION INNOVATION Project: Morpheus Hotel, Macau, China. Engineer: BuroHappold Engineering.

Project descrip on The fi h tower in Macau’s ‘City of Dreams’ leisure and entertainment complex stands 160 m high. The hotel accommoda on is arranged around a core in each wing of the building. The exoskeleton structure of the building works with two concrete cores, providing the main ver cal and horizontal load-bearing elements and upholding the client’s vision for a unique building. Judges’ comment “The Morpheus Hotel was recognised by the judges as being a forerunner in the new digital era of construction. The entire project from the initial visualisation of form, through the evolutionary development, analysis and design of different viable structural options, to the optimisation and bespoke manufacturing of the structural components and the control of their sequenced erection on site, could not have been accomplished without the formidable range of digital and communicational skills that characterise the structural engineer of today. When the unknown can be made known, the impossible can become possible and the value of the structural engineer is revealed in its true light. We look forward to the next step into the unknown!”

Morpheus Hotel, Macau, China. Image by Virgile Simon Bertrand.

THE AWARD FOR STRUCTURAL ARTISTRY (Building Structures) Project: Qingdao World Expo City, Qingdao, China. Engineer: China Architecture Design & Research Group. Project descrip on This cross-shaped exhibi on gallery connects 12 independent exhibi on halls. The gallery is open on all sides, forming an open light layout. The elegant prestressed cable-arch structural system uses triangular flexible es, PC plates on the roof, and diﬀerent connectors spreading all over the structure.

It is es mated that the use of the cables has permi ed a steel weight saving of up to half compared to a tradi onal arch structure. Cast steel components, from cable clamps to arch base pins have been skilfully pared down for the most compact of connec ons and have enabled quick and safe construcon on-site. The judges par cularly admired the simple elegance at the intersec on of the crossing galleries and the visual coherency of the structure”.

Judges’ comment “Arranged in a cruciform plan with a 500 m long, 47 m high primary gallery intersected by a 300 m long, 32 m high cross gallery, the structure creates a magnificent light-filled circula on area between large exhibi on halls. The primary gallery height is dictated by the surrounding buildings and being in a coastal area it experiences high wind loading. To maintain the lightest of structures, a novel prestressed cable arch was developed, with a fabricated box sec on of just 500 mm depth to span 48 m. 32

THE SINGAPORE ENGINEER January 2020

Qingdao World Expo City, Qingdao, China.

THE STRUCTURAL AWARDS 2019

The Award for Structural Ar stry (Non-building structures) Project: Vessel, New York, USA. Engineer: AKT II.

Project descrip on This interac ve sculpture creates a new innova ve centrepiece for the Hudson Yards redevelopment. Designed as a la ce of ramps and landings, forming a rigid, monolithic structure, Vessel is characterised by inner and outer layers of stairs comprising almost 2,500 individual steps. Judges’ comment The structural engineering challenges that were met to deliver this piece of urban inhabitable sculpture ranged through analysis, design and construc on. But for each of these, the uniqueness of the structure meant the challenges themselves were also unique.

Vessel, New York, USA. Image by Timothy Schenck.

The structure is the architecture and vice versa and with the form comparable to a massive spring, addressing vibra on was more complex than in other structures and was met with impressive engineering analysis and design”.

THE AWARD FOR SUSTAINABILITY

legacy within and beyond this specific project.

Project: La Reference, Ganthier, Hai . Engineer: Eckersley O’Callaghan.

Design decisions incorporated local materials and skill-availability, with the challenging design loads and respec ve detailing.

Project descrip on A charitable engineering project supported the construcon of a new secondary school in Hai , providing new classrooms to 150 students. Situated in a highly seismic zone and an area prone to hurricanes, the school’s resilience was paramount. Judges’ comment “This pro-bono-designed school project in Hai pulls together numerous poten al Structural Engineering aspects of sustainable design.

Limited resources required crea ve design approaches and innova ve solu ons to develop duc le connec ons resistant to earthquakes with minimal addi onal material from tradi onal seismic construc on. All this was achieved whilst coordina ng with other disciplines for natural ven la on, dayligh ng and acous c performance, ul mately providing a nourishing educaonal atmosphere”.

Following the recent devasta on caused by earthquakes and hurricanes, pragma c solu ons have been required in order to rebuild. This school project not only exemplifies a resistant structural solu on, but it does so in close collabora on with local engineers and construcon teams. All documenta on and processes were methodically designed to develop local understanding of structural behaviour and become educa onal tools for replica on, ensuring a social

La Reference, Ganthier, Hai . THE SINGAPORE ENGINEER January 2020

INFRASTRUCTURE PLANNING

THE FUTURE OF INFRASTRUCTURE

WILL BE SMART by Leona Frank, Senior Industry Marke ng Manager for Infrastructure, Autodesk With the global popula on expected to increase to 9.7 billion people by 2050, and with 6.4 billion people expected to live in ci es, the world must look at city planning and infrastructure in fundamentally diﬀerent ways. With the changing urban landscape, ci es must transform to be more accessible and produc ve to serve their ci zens’ rising needs. Technology is a cri cal ingredient for ci es to address the con nued demands they will face over me. Through access to data and leveraging technologies such as Building Informa on Modeling (BIM) and Geographical Informa on Systems (GIS), ci es can become smarter to foster community engagement, make work easier, and urban life be er. With connected and smart ci es becoming more prevalent, what role does smart infrastructure play? Autodesk, a world leader in 3D design, engineering and entertainment so ware, and Esri, a world leader in GIS, announced a strategic alliance in November 2017 to enable improved interoperability between BIM and GIS pla orms and so ware. But why does this ma er? There is a natural convergence between BIM and GIS happening in the industry. BIM is best suited in the project planning, design and engineering, and construc on phase, while GIS is best suited to scale ac vi es, such as urban planning and asset management. Bringing the two together will provide industry and city planners the ability to design in the context of the real world and build more connected ci es and infrastructure with a focused eye on sustainability. Dr Ken Henry, former Secretary, Department of Treasury, Australia said, “The role of technology is central to the task of making sure that infrastructure investment has something to do with the kind of society, and the kind of capabili es we need to provision, in order to combine the growth, sustainability, inclusion and innova on that the ‘world of the future’ demands”.

ac onable. We support smart city ini a ves by providing the pla orm to create, communicate and evaluate those op ons that result in a more connected, sustainable and resilient community. The management of data aids quicker project design concept crea on and faster ve ng and approval, while suppor ng community and city development. Smart infrastructure will benefit growing communi es and ci es, now and into the future, in a number of ways. Some of the possibili es are presented below. • More people create more strain on our infrastructure - roads, highways etc. By incorporating sensors, we can understand how infrastructure is being used and how often maintenance needs to be performed. With more than USD 218 trillion worth of existing infrastructure assets requiring care and upkeep in the world’s top 32 countries, the need to do things differently is critical. • IoT is already improving our lives through intelligence around parking and transporta on - but there is so much more poten al. With IoT, infrastructure can ‘talk’ to infrastructure for be er decision-making. When you put enough sensors on structures, they can tell you about the environment around it and how people are

An example of smart infrastructure is the MX3D bridge - the world’s first 3D printed steel bridge. Equipped with sensors, the bridge streams data to the cloud where it is then processed and interpreted to visualise intelligence about bridge traﬃc, structural integrity and the surrounding neighbourhood and environment. Ci es are o en overwhelmed with big data and the ability to make it 34

THE SINGAPORE ENGINEER January 2020

The MX3D team presen ng the finalised bridge project. Image by MX3D.

INFRASTRUCTURE PLANNING

interac ng with infrastructure to create eﬃciencies. For example, bridges can ‘talk’ to roadways to be er me the func oning of lights and minimise traﬃc during peak hours. • Natural disasters such as earthquakes, hurricanes and tornados, take a toll on our infrastructure. Imagine being able to use data to be er understand infrastructure weak points to build be er, stronger infrastructure in the future. Designing roads and bridges for longevity starts with op mising data exchange between BIM, CAD, and GIS. • Sensor data will inform where new structures are built, based on how they are being used by city dwellers.

This informa on will also allow future infrastructure to adapt more easily to supply and demand and changing demographic or environmental condi ons. Smart infrastructure interconnec ons, at a personal, community, metropolitan, or even na onal level, underpinned by technology, will change the vision of smart ci es and provide the founda on for even more holis c planning of smart ci es where all kinds of infrastructure - energy, water, transporta on, buildings and governance – are ‘talking’ to each other to op mise and priori se needs and performance, minimise energy use and make life more enjoyable and produc ve for the people who live in them.

Autodesk and Esri partner to advance infrastructure planning and design In late 2017, Autodesk Inc and Esri Inc announced the start of a new rela onship to build a bridge between BIM and GIS mapping technologies. Together Autodesk and Esri plan to enable a broad range of industries to gain be er context by visualising data of the man-made world, the environment, ci zens and the networks that weave it all together. “It is important to consider the needs of future genera ons during the design and building of projects today. The benefits of partnering with Autodesk will include securing sustainable resources for the growing popula on, a responsible human footprint on our natural environment, be er use of our planet’s resources and more resilient ci es”, said Jack Dangermond, President, Esri. For infrastructure owners around the world, both public and private, enabling BIM and GIS mapping so ware to more seamlessly work together will opmise their ability to plan, design, build and operate infrastructure assets, saving precious me and money. Improving the integra on of Esri and Autodesk so ware has the poten al to decrease workflow mes. “Partnering with Esri is intended to combine the power of BIM and GIS mapping which will enable our shared customers to build anything, anywhere. Our goals are to provide industry and city planners the ability to design in the context of the real world. This will allow communi es to build more connected, resilient ci es, and infrastructure with a focused eye on sustainability”, said Andrew Anagnost, CEO, Autodesk. “In a city like Singapore where land is limited, ensuring that the urban environment meets the needs of not just today, but future demands as well, is key. Beyond taking into account the physical space needed, it is important to consider the devel-

opment’s surroundings”, said Thomas Pramotedham, Chief Execu ve Oﬃcer, Esri Singapore. “The partnership between Esri and Autodesk frees the flow of data between geographic informa on systems (GIS) and building informa on modeling (BIM) to help architects, builders, city planners and engineers understand the interface between the built and natural environments. This means designers and architects have greater insight to influence a structure’s loca on, orienta on, and even construc on materials”, he added. “As Singapore moves closer to being a Living City where sensors and devices feed real- me data, the integra on of BIM and GIS will ingest this informa on to add context to our environment helping us design and construct resilient and liveable communi es for genera ons to enjoy”, Mr Pramotedham con nued. Autodesk and Esri will work together to be er integrate their respec ve technologies, allowing industry professionals to synthesise informa on from both BIM and GIS to enable a more connected infrastructure. Benefits are expected to include improved stakeholder engagement, more sustainable and resilient design through enhanced project insight, and reduced risk via improved end-to-end flow of materials, resource availability and scheduling during construc on. “I am thrilled to learn of the Autodesk and Esri strategic partnership. At AECOM, we value innovative spirit, and I am optimistic that this new strategic partnership will produce dynamic software synergies. The combined technology sets has the potential to provide new ways of connecting information across the project lifecycle to the benefit of our clients”, said John Kizior, Global Director, Project Technologies, AECOM.

THE SINGAPORE ENGINEER January 2020

RECYCLING TECHNOLOGIES

TECHNOLOGIES FOR THE DIFFERENT PROCESSING STAGES IN ASPHALT RECYCLING In order to turn aggregates and bitumen into asphalt for road construc on, a thermal mixing process is needed - this is what an asphalt mixing plant is used for. When it comes to the produc on of this ‘black gold’, an increasing number of companies around the world are discovering that reclaimed asphalt pavement (RAP), is a valuable resource. In addi on, industrialised na ons are rehabilita ng far more miles of road than they are building new ones. Millions of tons of asphalt are being removed - a job primarily performed by cold milling machines. They are the first link in the process chain which con nues with crushing and screening plants as well as asphalt mixing plants in the next step and ends with the reclaimed asphalt being repaved by pavers as part of the new mix. Machines designed to work together, innova ve processes, and state-of-the-art technologies all have a major impact on the eﬃciency of this process chain. Smooth processes make it possible to increase the cost-eﬀec veness and sustainability of asphalt recycling.

Increasing the feed volume of RAP In many countries, virtually every truck that transports asphalt mix on a site has at least some recycled asphalt on it. In Germany alone, for example, a quarter of the total asphalt produced in 2018 (41 million tons) contained RAP (10.5 million tons). With a total of around 12 million tons of asphalt pavement removed in 2018, this represents a recycling rate of 87%. Recycling old asphalt is an economic impera ve in order to conserve natural resources. As a result, the industry is constantly looking for solu ons to op mise the processes within the asphalt mixing plant. One of the main approaches is to increase the volume of reclaimed asphalt pavement used in all of the diﬀerent recipes produced using ‘hot and cold’ processing technologies. Using the maximum amount of old asphalt not only protects the environment, it also posi vely aﬀects asphalt mix prices. In the tradi onal parallel flow recycling method, the temperature is limited to 130° C due to the exhaust gas emissions, but the exhaust gas temperatures are physically higher, which leads to increased energy consumpon and the need for addi onal de-dus ng. In order to achieve a mix temperature of 160° C, white mineral must be overheated in this case.

The counterflow method Unlike conven onal parallel recycling drums, in a recycling drum with hot gas generator, the recycled material is heated indirectly using the counterflow method, meaning that the material in the drum flows towards the heat source. This makes it possible to achieve higher material temperatures while simultaneously reducing 36

THE SINGAPORE ENGINEER January 2020

A good process chain, involving solu ons for the removal of the old asphalt to its treatment and mixing, and paving of the new asphalt, makes it possible to increase the cost-eﬀec veness and sustainability of asphalt recycling.

the exhaust gas temperature. The ou low temperature of 160°C corresponds to the temperature of subsequent processing, while the exhaust gas temperature lies above the dew point at approximately 100°C. The en re process is possible only by using a hot gas generator, because direct firing would burn the recycled material and make it unusable. The burner, hot gas generator, recycling drum, extrac on hood, and the recircula on and exhaust air system are all designed to work in harmony. One posi ve eﬀect is that the white mineral no longer has to be overheated, which results in a significant reduc on in energy consump on. Recycling using the counterflow method reduces emissions (as required by Germany’s Technical Instruc ons on Air Quality Control regula on) and, depending on the quality of the recycled material, achieves recycling rates of 90 + X%. This makes an investment in the equally green and eﬃcient technology par cularly a rac ve.

RECYCLING TECHNOLOGIES

And the technology becomes even greener when the upstream process steps are implemented using state-ofthe-art processes and technologies.

Screening plants The maximum theore cal amount of RAP that can be added to the mix depends largely on its par cle-size distribu on (PSD), or, to put it another way, on the quan ty, size, and composi on of its cons tuents. As a result, one goal must be to align the PSD curve of the crushed RAP as closely as possible to the desired PSD curve of the final asphalt product. This is where mobile screening plants come into play. They ensure that the mixing plants are able to directly process up to 80% of the reclaimed asphalt (milled material). This significantly reduces process costs compared to post-processing all of the milled material.

Cold milling machines like Wirtgen’s W 210i, with their ability to selec vely mill the surface, binder, and base layers, as well as their intelligent milling technologies, help ensure that the RAP can be recycled cost-eﬀec vely in the asphalt mixing plant.

In the case of complete post-processing, ie also of the remaining oversize grain, impact crushers equipped with a secondary screening unit would also be used.

Intelligent milling for cost-effec ve and sustainable recycling First, however, the RAP must be recovered by removing individual layers of the road structure. By removing the asphalt in layers, using cold milling machines, the milled material can be fed into the material cycle for reuse, separately, for each type of mix, depending on its structural suitability and its qualita ve proper es. The selec ve recovery of the surface course, binder course, and base course alone offers significant environmental and financial advantages. If intelligent milling technology is also taken into account, it increases the cost-effec ve reuse of the milled material in the asphalt mixing plant even further. This is largely due to the cold milling machines’ load-dependent water sprinkling system. In this context, the water used to cool the picks varies depending on the engine load and milling speed. Water consump on can be significantly reduced by automa cally ac va ng the water system when the milling drum is in use or by switching it off when the milling opera on stops. Specifically, this can cut water consump on by up to 20%. As a result, the service life of the picks is extended, the cold milling machine’s water tanks have to be filled less frequently, and down mes are shorter. This not only pleases the milling machine operator, but also the master mixer in charge of the asphalt mixing plant. They benefit from the low water consumpon because it means the milled material has a 3% to 4% lower residual moisture content per ton of asphalt. Without the use of state-of-the-art milling technologies, the residual moisture level would be higher. The formula applicable to the drying process required to produce the new asphalt in the asphalt mixing plant is simple. Material that is 1% drier saves 1 lire of hea ng oil per ton of finished asphalt during subsequent processing into recycled mix, as well reduces CO2 emissions due to the process requiring less energy.

Screening plants like the MOBISCREEN MS 953 EVO screen the milled material to achieve an op mum PSD curve, making it possible to increase the amount of RAP added to the asphalt mix.

Asphalt mixing plants like the sta onary BA RPP 4000 produce up to 320 tons of asphalt per hour. When recycled material is incorporated, using the counterflow method, with a hot gas generator and a recycling rate of 90 + X%, the new mix can consist of around 300 tons of RAP, depending on the recipe.

Asphalt pavers like the SUPER 1800-3i and tandem rollers like the HD+ 90i PH VO or DV+ 70i VV-S, as well as pneuma c tyre rollers like the HP 280i, pave and compact the recycled asphalt at the end of the process chain.

All images by the Wirtgen Group THE SINGAPORE ENGINEER January 2020

PROJECT APPLICATION

CONSTRUCTING AND FINISHING

THE NEW ISTANBUL AIRPORT A wide range of chemical products was used in the first phase.

A view of the whole Istanbul Airport during the construc on stage.

The first sec on of Istanbul’s new airport, designed to become the world’s largest, in terms of annual passenger capacity, was oﬃcially inaugurated on 29 October 2018. Star ng with the so launch and un l full comple on, the airport is expected to be opened in four phases. Phase 1 was completed with 1.4 million m2 of terminal space, an ATC (Air Traﬃc Control) tower, support facili es and two runways. Phases 2 and 3, featuring two additional air traffic control towers and two additional runways, will be completed between 2021 and 2022. By 2028, the airport is expected to be fully completed, with the sixth runway, as well as the opening of a satellite terminal. With an annual capacity of up to 200 million passengers, Istanbul’s new airport will offer flights to more than 350 destinations and will also be home to the world’s largest duty-free shopping complex. The 53,000 m2 shopping complex will consist of six sections, including luxury stores and bazaars.

An unprecedented project Istanbul’s new airport aims to establish itself as a major travel hub and a key player on the world avia on stage. Once completed, it will be spread over an area of 76 km2, and will house the world’s largest terminal under one roof. 38

THE SINGAPORE ENGINEER January 2020

“From an airport planning perspec ve, the project is unprecedented, both in terms of its size and the speed with which the project was a empted”, said Dr Thomas Budd, Lecturer in Airport Planning and Management, Centre for Air Transport Management, Cranfield University, UK.

Chemical products for a variety of applica ons Mapei Yapı Kimyasalları A S, the Turkish subsidiary of the Mapei Group, began supplying products to the project in 2016 and con nued in 2017 by providing products and systems for a broader scope of applica ons. Mapei is a global supplier of building products, with a presence in many countries including Turkey. MAPEFIX VE SF chemical styrene-free vinylester anchor was chosen for bars which had been installed throughout the project. Due to its quicker se ng me, this product provided great advantage in comparison with tradi onal epoxy-based chemical materials. MAPELASTIC FOUNDATION two-component, flexible cemen ous mortar was used for waterproofing concrete surfaces in the water tanks which were subject to both posi ve and nega ve water pressure. Prior to the applicaon of MAPELASTIC FOUNDATION, PRIMER 3296 acrylic primer with strong penetra ng ac on was applied to level oﬀ the surface and improve its bonding proper es.

PROJECT APPLICATION

MAPELASTIC FOUNDATION was chosen to waterproof concrete surfaces in the water tanks.

AQUAFLEX ROOF PREMIUM was used for waterproofing several surfaces in the ATC tower. Image by Shu erstock.

A er applying MAPELASTIC FOUNDATION, either MAPECOAT I 24 or MAPECOAT DW 25 was used for the protecon of the waterproofing layers during their service life. MAPECOAT I 24 two-component epoxy paint has high resistance to aggressive chemical agents. MAPECOAT DW 25 is a two-component epoxy paint used to form a coating on concrete surfaces that are in contact with drinking water and food products. MAPEPROOF SWELL single component hydro-expansive paste was used to solve the delicate problem of waterproofing pipe inlets and outlets. MAPEPROOF SWELL was specially developed to form flexible, waterproof seals in cracked reinforced concrete or in precast elements with infiltra on of water.

The Air Traﬃc Control tower The site’s landmark Air Traﬃc Control tower was designed by Pininfarina and AECOM. The design was selected from six solu ons proposed by interna onal architecture studios, including Zaha Hadid, Fuksas, Moshe Safdie, Grimshaw Architects and RMJM. The project won the pres gious Interna onal Architecture Award 2016, promoted by the Chicago Athenaeum (the Interna onal Museum of Architecture and Design) and the European Centre for Architecture, Art Design and Urban Studies. The design concept of the tower features elements evoca ve of Turkish culture and is inspired by the tulip which has been a symbol of Istanbul for many centuries and an important cultural reference in Turkish history. The shapes of the flower were redesigned and reinterpreted through Pininfarina’s iden ty, based on its profound knowledge in automo ve design and wind tunnel modelling, as well as on the influence inherited from aerodynamic shapes used in aeronau cal design. Mapei’s AQUAFLEX ROOF PREMIUM ready-to-use, water-based polyurethane waterproofing membrane was used for waterproofing several surfaces in the ATC tower as it is a good solu on for both old and new surfaces with slopes or irregulari es. MAPECOAT I 600 W two-component transparent epoxy primer in water dispersion was used on the surfaces

KERACOLOR FF grout was used to grout the joints in in all the ceramic coverings in the project.

as an adhesion promoter and MAPEFLEX PU 40 polyurethane sealant with a low modullus of elas city was chosen for sealing expansion and contrac on joints. KERACOLOR FF high performance, polymer-modified, water-repellent, cemen ous mortar was used for grouting joints in all the ceramic le coverings in the project. ELASTORAPID high-performance, two-component, highly deformable, cemen ous adhesive with extended open me, was used for bonding ceramic les in some piers.

Waterproofing the terraces For waterproofing the green terraces which cover about 75,000 m2 in the departures area, PURTOP 400 M two-component, solvent-free, spray applied, hybrid polyurea membrane was the selected product. It has good resistance to alkalis and dilute acids and an elonga on capacity higher than 400%. Besides, it has been cer fied as conforming to CEN/TS 14416 Standards for resistance to root penetra on, which was mandatory for green terrace applica on in this project. Before using PURTOP 400 M, PRIMER SN two-component fillerised epoxy primer was applied on the substrates. MAPEFLOOR FINISH 55 highly flexible polyurethane finish was used as a final protec ve layer for a 2000 m2 area where colour protec on was needed. THE SINGAPORE ENGINEER January 2020

PROJECT APPLICATION

PURTOP 400 M hybrid polyurea membrane was used for waterproofing the substrates in the green terraces. Image by Shu erstock.

AQUAFLEX ROOF PREMIUM AQUAFLEX ROOF PREMIUM is a ready-to-use, solvent-free, liquid waterproofing membrane, without VOC emissions. Once applied, it forms a seamless membrane, with 400% elonga on capacity, that is resistant to atmospheric agents, UV rays and ponding water. It is also resistant to foot traﬃc and may be applied on all walkable areas without an addi onal protec ve layer. Its good mechanical characteris cs remain stable over the years, which makes the product highly durable.

PROJECT DATA PROJECT Istanbul Airport, Istanbul, Turkey Construc on period 2016 to 2028 Client IGA-Istanbul Great Airport Design Nordic Oﬃce-Grimshaw-Hap c Architecture Pininfarina-AECOM Works direc on Horizontal Main contractor Cengiz Mapa Limak Kolin Kalyon Joint Venture

THE SINGAPORE ENGINEER January 2020

INTERVENTION BY MAPEI Period of the Interven on 2016-2018 Contribu on by Mapei Supply of products for substrate prepara on, waterproofing surfaces in tanks and terraces, chemical anchoring, installing and grou ng ceramic les, sealing joints and coa ng walls. Installa on company Umut Yali m Mapei distributors Umut, Himerpa, Pelenkoğlu Mapei coordinator Emrah Karatas, Mapei Yapı Kimyasalları A S, Turkey Mapei products used Preparing substrates - PRIMER SN, PRIMER 3296 Sealing joints and anchoring - MAPEFLEX PU 40, MAPEFIX VE SF Installing and grou ng ceramic les - ELASTORAPID, KERACOLOR FF Waterproofing substrates - MAPELASTIC FOUNDATION, MAPELASTIC, MAPEPROOF SWELL, PURTOP 400 M, AQUAFLEX ROOF PREMIUM Coa ngs - MAPECOAT I 24, MAPECOAT DW 25, MAPECOAT I 600 W Finishing floors - MAPEFLOOR FINISH 55 Website for further informa on www.mapei.com

This editorial feature is based on an ar cle from Realtà MAPEI INTERNATIONAL Issue 74. Images by Mapei, unless otherwise stated.

PROJECT APPLICATION

SWEDEN’S BIGGEST ROAD AND TUNNEL PROJECT A 21 km motorway bypass is being constructed to relieve traffic in Stockholm - the E4 Bypass Stockholm, or in Swedish, ‘E4 Förbifart Stockholm’. The bypass, scheduled for comple on by 2030 stands out as one of Sweden’s biggest infrastructure projects and its 18 km of tunnel will make it the world’s second longest urban road tunnel. Stockholm has the fastest growth rate in Europe. The 14 islands that make up the Stockholm region are currently home to over a fi h of the Swedish popula on, with 2.1 million inhabitants. By 2030, this is expected to grow to around 2.5 million. For the region to con nue to develop, well-func oning infrastructure is essen al, and major investments are being made in Stockholm. For example, local public transport has been improved by a new railway through Stockholm’s central districts, the Citybanan, which was officially opened in 2017. Although the Citybanan represents an important step towards improving public transport systems, it is not sufficient to combat the increasing car traffic in the city. Stockholm currently has only one major road artery - Essingeleden. The road was opened in 1967 and is designed for 80,000 vehicles per day. Fi y years later, around 160,000 vehicles travel on it on a typical working day and the number is rising. Consequently, the transport system in Stockholm is extremely vulnerable, with Essingeleden, in par cular, having become very sensi ve to road accidents. To address this situa on, a 21 km motorway is being constructed, that will link the south of the city (Skärholmen) with the north (Häggvik). The new road, E4 Bypass Stockholm, will divert traffic away from the city centre to the west.

ONE OF THE LONGEST ROAD TUNNELS IN THE WORLD Most of the bypass - 18 km of the 21 km - will run through tunnels, making the bypass the world’s second longest urban road tunnel, behind Tokyo’s Yamate Tunnel. The link will consist of twin tunnels, with its deepest point beneath Lake Mälaren, lying almost 70 m below sea level. Each tunnel will have three lanes of traﬃc in each direc on, suppor ng an an cipated traﬃc flow of 140,000 vehicles daily. During the construc on work, 22 million tonnes of rock had to be excavated. Doka Sweden won the contract to provide formwork to four sec ons - FSE105 Kungens Kurva (King’s Curve), FSE502 Hjulsta Norra (North of Hjulsta), FSE61 Akalla and FSE62 Häggvik.

FSE105 Kungens Kurva (King´s Curve) Interchange King´s Curve is the largest of the four contracts. The project includes a traﬃc area with a roundabout bridge and ramps, a concrete trough 350 m long and two concrete tunnels 330 m long.

The project includes a 20 m bored tunnel at the Interchange King´s Curve.

Client Skanska Sec on data Rock excava ons - 300,000 m³ Soil excava ons - 375,000 m³ Concrete - 78,000 m³ Sheet pile - 14,500 m² Concrete tunnels - 2 x 330 m Formwork in use Framax Xlife Framax Xlife plus Large-area formwork Top 50 Load-bearing tower Staxo 40 Load-bearing tower Staxo 100 Formwork traveller THE SINGAPORE ENGINEER January 2020

PROJECT APPLICATION

FSE502 Hjulsta Norra (North of Hjulsta) Sec on FSE502 ‘North of Hjulsta’, where European Routes E4 and E18 meet, will be one of Sweden’s most important interchanges. The project sec on includes a 200 m concrete tunnel, and the challenge was to supply two formwork travellers that could be used to concrete the walls and ceiling simultaneously. The client also wanted to be able to move the travellers once a week. To achieve this, the travellers were fi ed with hydraulic systems that could be used to complete the formwork work rapidly and logically. Client NCC Sec on data Construc on method - par ally monolithic Tunnel with formwork - 2 x 370 m Length of concrete sec ons - 10 m Number of concrete sec ons - 2 x 38 Trough - 170 m Formwork in use Framax Xlife Frami Top 50 Staxo 100 Formwork traveller

PROJECT DATA PROJECT E4 Bypass Stockholm -FSE105 Kungens Kurva -FSE502 North of Hjulsta -FSE61 Akalla -FSE62 Häggvik Loca on Stockholm, Sweden Type of project Tunnel and road construc on Total motorway length 21 km Es mated traﬃc 140,000 vehicles/day (by 2035) Total tunnel length 18 km Total volume of rock 22 million tonnes Start of construc on Q3/2015 Scheduled comple on of construc on Q4/2030

PROJECT CREDITS Principal Trafikverket Swedish Transport Administra on (STA) Construc on companies Skanska NCC Züblin Scandinavia AB

The formwork travellers were used to concrete the walls and ceiling simultaneously. 42

THE SINGAPORE ENGINEER January 2020

All images by Doka

PROJECT APPLICATION

FSE61 Akalla and FSE62 Häggvik An elliptical flyover is being built in Akalla above the local Stockholm traffic. This project section includes construction of around 950 m of motorway, major shoring measures for the excavation work, a tunnel around 120 m long built using the cut-and-cover method, the 480 m cutting for the tunnel entrance, and a roundabout. Work for the tunnel and cutting meets extensive specifications for impermeability and anchoring. Construc on from Häggvik towards the flyover is progressing through a deep rock gorge alongside the Hansta nature reserve. The work is being carried out in a highly challenging traﬃc environment, where access for traﬃc must be guaranteed at all mes. On average, over 100,000 vehicles pass the site each day.

Reinforcement - 11,600 t Soil and Rock excava on - 715,000 m³ Rock tunnel excava on - 11,100 m³ Sheet pile - 8,745 m² Formwork in use Frami Framax Xlife Top 50 Staxo 100 Formwork traveller Sec on data (FSE62 Häggvik) Rock excava ons - 320,000 m³ Soil excava ons - 250,000 m³ Sheet pile - 3,500 m² Concrete - 29,000 m³

Sec on data (FSE61 Akalla) Concrete - 60,000 m³

Formwork in use Frami Framax Xlife Top 50 Staxo 100 Formwork traveller

The Akalla project sec on includes a cut-and-cover tunnel around 130 m long.

Two concrete tunnels, four bridges, suppor ng walls, and fire and sound insula on are being planned and built in Häggvik.

Clients Züblin Scandinavia AB NCC

THE SINGAPORE ENGINEER January 2020

PRODUCTS & SOLUTIONS

MANITOU ASIA PRESENTS

SMART AERIAL WORK PLATFORM SUITE Manitou Asia, part of the Manitou Group, a world leader in rough terrain handling, held an inaugural showcase for its innova ve range of Aerial Work Pla orms (AWP) recently, at the Manitou Center Singapore. This marked a milestone in Manitou’s expansion into the AWP market to be er serve the construc on and industrial sectors in Asia.

In September 2019, Manitou Group started the construc on of a new factory dedicated to AWPs in Candé (Maine-et-Loire), France, as part of its global investment plan. To be completed by the first quarter of 2021, this new industrial facility will enable the group to respond to AWP market growth in markets including Asia.

Manitou displayed a total of nine AWPs at the event. Each machine is built to realise enhanced safety, ease of use, reduced maintenance, operator comfort, increased productivity and reduced Total Cost of Ownership (TCO) for its users. In addition, Manitou’s fleet of smart AWPs have been developed as ‘Connected Machines’ to allow users to fully harness the benefits offered by the Internet of Things (IoT). They can provide real-time access to machine data, remote monitoring for better service levels and maintenance data on mobile apps. This means that users can track and trace their machines, enjoy anticipative maintenance to reduce downtime and achieve higher return on investment. At the event, Manitou also announced the introduc on of its first electric all-terrain aerial pla orm to Asia - the ‘Oxygen 200ATJ E’. Designed as a 100% electric mobile all-terrain eleva ng work pla orm, ‘Oxygen’ will address the growing demand in Asia for flexible low-carbon solu ons and accelerate users towards their goals of sustainability and eﬃciency. The Oxygen 200 ATJ E is a versatile machine for indoor, outdoor and urban use due to its zero emission and noise cancellation capability. It also offers improved TCO with its zero fuel consumption, improved onboard diagnostics and reduced preventive maintenance. ‘Oxygen’ is suitable for many types of work such as cladding, framework, painting, cleaning, pruning, events, airport maintenance, port maintenance, industrial maintenance and urban worksites. 44

THE SINGAPORE ENGINEER January 2020

The Oxygen 200 ATJ E is a versa le machine for indoor, outdoor and urban use due to its zero emission and noise cancella on capability. Top image by Manitou Group. Bo om image by Manitou Group, bauma 2019.

PRODUCTS & SOLUTIONS

CATERPILLAR TO PRESENT NEW PRODUCTS AT CONEXPO CON/AGG 2020 The Caterpillar exhibit at CONEXPO-CON/AGG 2020 will include a mix of sta c displays, equipment demonstraon area, and new services/technologies under the theme of ‘Your Work Ma ers’. The 60,000 2 (5574 m2) exhibit in the show’s new outdoor Fes val Grounds includes Operator’s Stadium, where the finals of the Global Operator Challenge and equipment demonstra ons take place. Caterpillar is inves ng in technology and safety features showcased in more than 30 Cat machines on display, including nine new product introduc ons from the dozer, excavator, ar culated truck and backhoe loader families.

A wide range of new models Successor to the Cat D5K2, the new Cat D3 dozer is characterised by grading accuracy and efficiency. The operator cab delivers greater visibility, while enhanced controls deliver easier, intui ve finish grading. Powertrain advancements improve fuel efficiency by up to 10% over previous models. The new centre-pivot 420XE backhoe loader now offers seat-mounted controls for low-effort machine control to boost operator efficiency and reduce fa gue. Dual Mode opera on increases machine produc vity, while electronic loader controls offer true parallel li . A new IT quick coupler delivers quick change-out of a large por olio of Cat a achments. The new 150 AWD motor grader features an all-wheel drive that assists with trac on and manoeuvring, allowing the machine to work in any environment. Eco mode is said to deliver up to 10% greater fuel efficiency without produc vity loss, and owning and opera ng costs are reduced via new filters and longer service intervals. The new mastless 3D Cat GRADE control system unleashes the poten al of the mouldboard to give it full range of mo on. The GNSS receivers are bolted to the machine, which increases up me and reduces costs associated with poten al receiver, mast or machine damage when using the dual 3D GNSS system. The integrated 3D Cat GRADE will ini ally be available on the 140, 150 and 160 joys ck motor graders. The new 725 ar culated truck offerings include new cab features such as assisted hoist, Automa c Retarder Control and Advanced Automa c Trac on Control, which improve operator experience and reduce operator ac ons. Performance improvements

include up to 9% increased speed on grades, 8% improved accelera on and a 7% produc vity increase.

Five hydraulic excavators to debut Caterpillar will introduce five new wheeled, small, medium and large hydraulic excavator models at CONEXPO-CON/AGG 2020. The new Cat M318 wheeled excavator is said to improve operator eﬃciency by up to 45% with Cat GRADE, E-Fence and PAYLOAD op ons and deliver up to 10% lower maintenance costs with longer service intervals. The new 313 GC is said to deliver low owning and opera ng costs through a simple design that is easy to operate, maintain and own. The new 315 boasts a 13% larger cab and improved performance with up to 10% more swing torque and up to 14% more drawbar pull. Advanced engine technology and control system for the new 325 medium excavator is said to reduce fuel consump on by up to 25%, while a precise combina on of lower engine speed and large hydraulic pump pressure and flow delivers more work per unit of fuel. Extended maintenance intervals means ge ng more work done with up to 20% lower maintenance costs. The new 395 excavator is built to move tons of material quickly and eﬃciently. With 10% more swing torque and 10% more s ck force than the model it replaces, operators will experience faster cycle mes with bigger buckets for greater ground-breaking power and producon. Cat PAYLOAD also comes standard so operators can validate produc on at the end of every shi . Plus two mes more structural durability means longer service life, and extended service intervals lower maintenance costs by up to 20%.

The new 150 AWD motor grader features an all-wheel drive that assists with trac on and manoeuvring, allowing the machine to work in any environment. THE SINGAPORE ENGINEER January 2020

PRODUCTS & SOLUTIONS

LIEBHERR STRENGTHENING ITS

LTM 1750 9.1 MOBILE CRANE The Liebherr LTM 1750-9.1 mobile crane is ge ng stronger. The use of refined sta c calcula on methods means that li ing capacity values have been increased across almost the en re working range. The LTM 1750-9.1 is becoming an 800 tonner, with the type designa on LTM 1750-9.1 being retained. Liebherr has compiled a new luﬃng jib configura on using exis ng la ce sec ons to provide addi onal capacity increases for wind power applica ons. Cranes already in use on the market can be retrofi ed with the new system. The wide-ranging experience that design engineers and structural engineers have with thin-walled boom profiles has enabled the popular calcula on models and approaches to the Finite Element Method to be further refined. Supported by high-performance computers, the real-load-bearing structure of the crane is simulated even be er in the sta c calcula on model. The company has now transferred the latest findings and methods, which had already been applied in the LTM 1650-8.1 presented at bauma, to the LTM 17509.1, which was brought to market in 2012. The most recent calcula on standards have also been taken into considera on.

a higher load capacity class in the area of wind power applica ons. So, for example, more than 10 tonnes of addi onal load capacity can be generated for the moun ng of wind turbines on 90 m and 100 m high towers. The LTM 1750-9.1 is also much stronger in the area of heavy load li ing. The gain in load capacity in such applica ons is in excess of 7 tonnes. Liebherr now oﬀers load capacity tables for three wind veloci es for this crane and for the latest new developments, giving the customer significant support in both job planning and opera on.

The result is that the li ing capaci es of the 750-tonner are now higher than originally calculated across the vast majority of working ranges. The new load capacity tables also contain a table with the nominal max load capacity of 800 tonnes. Operators of the LTM 1750-9.1 now have the possibility to update the crane so ware with the new tables and, if necessary, to add any addi onal equipment required. Thanks to the new luﬃng fly jib configura on, the LTM 1750-9.1 has moved into 46

THE SINGAPORE ENGINEER January 2020

The increase in load capacity of the LTM 1750-9.1 for wind power applica ons is more than 10 tonnes.

PRODUCTS & SOLUTIONS

THE CTLH 192 12 LUFFING JIB TOWER CRANE Terex Cranes has presented its first luffing jib tower crane with hydraulic luffing technology. Specifically designed for inner-city construc on sites, this new model reaches the lowest in-service and out-of-service radius, of only 3 m and 8 m, respec vely. The company said it focused its R&D efforts to develop a model that is tailor-made for the high-demand markets where space issues are of primary importance and the crane is required to work on constrained areas and even with mul ple cranes. The CTLH 192-12, with a jib length from 25 mm to 55 m (82 to 180 ), can deliver a maximum 12 t (13.2 US ton) and up to a 2.35 t (2.59 US ton) load at the maximum 55 m (180 ) jib length. The company’s Terex Power Plus (TPP) func on will temporarily allow for an increase of the li ing capacity by approximately 10%, giving the operator extra li ing capacity just at the touch of a bu on. The hydraulic luffing technology offers key advantages in terms of reduced occupied space, both in-service (up to only 3 m) and out-of-service (up to only 8 m). This technology also allows the operator to manoeuvre the crane with greater precision and readiness, as well as providing high performance for li ing significant loads both at the maximum and at the jib p. The CTLH 192-12 has also been designed to op mise assembly and dismantling opera ons, as most of the parts are quickly assembled on the ground and the full crane erec on can be completed with few li s.

the Terex Power Plus func on, also the Easy Setup and the Terex Power Match, and is ready for An -Collision and Zoning systems. Hoist, slewing and luffing speeds are designed so that operators can move and posi on heavy loads efficiently and precisely. The crane’s new control system features expanded configura on op ons, allowing the CTLH 192-12 to efficiently and quickly adapt to different jobsite needs. The new Terex Slewing technology enhances the control of the crane on varying job sites condi ons, adjus ng the responsiveness of the crane to operator preferences or, for example, to wind condi ons, fine-tuning the speeds, the accelera on and the counter-manoeuvre. The model can be configured with HD23, TS23, TS21 and H20 masts, from 2.0 m to 2.3 m (6.6 to 7.6 ) widths, and with several op ons for basement, from founda on anchors to various chassis types from 4.5 m (14.8 ) to 8 m (26.3 ) base selec ons, so that customers can efficiently manage component inventory while cost-effec vely mee ng tower height needs. The crane can be equipped with the op onal T-Link Pla orm for remote control of crane fleet data any me and from anywhere via web, to op mise efficiency and reduce costs. A wide range of real- me data and a variety of analyses are visualised to assess the fleet’s performance.

Maintenance is also simplified on the CTLH 192-12, thanks to the high reliability of all hydraulic components and clever solu ons such as the auxiliary hydraulic system in addi on to the main one, to ensure con nuity of opera on in any condi on, and the dedicated system for oil cooling and oil hea ng to keep the unit opera onal whatever the external ambient temperature. For extremely cold temperatures, a dedicated ‘low temperature’ oil is available as an op on. The CTLH 192-12 features the ergonomic S-Pace cab with new advanced electronic controls including, besides

The CTLH 192-12 luﬃng jib tower crane has been developed with several advanced features. THE SINGAPORE ENGINEER January 2020

IES UPDATE

IES COMMEMORATES DUTCH FRIENDSHIP WITH JOINT FORUM ON PROFESSIONAL DEVELOPMENT AND CROSS BORDER MOBILITY Marking the first anniversary of IES’ partnership with the Royal Netherlands Society of Engineers (KIVI), a forum was held on 2 December 2019 at Mandarin Orchard Singapore, tled “Professional Development & Mobility for Engineers”. It was a ended by more than 120 engineers, with Senior Minister of State for Trade and Industry and Educa on, Mr Chee Hong Tat, and the Dutch ambassador to Singapore, Ms Margriet Vonno, gracing the event as dis nguished guests. Against the backdrop of con nuous professional development (CPD) and cross-border mobility of engineers, Mr Chee paid homage to local engineers for contribu ng to Singapore’s development, and noted the importance of keeping up with global engineering and technology trends.

Mr Danny Lee, the Vice Chairman of the Steering Commi ee for the Na onal Career Progression Pathway for Technologists and Technicians, updated everyone present about its progress and the proposed framework. The forum then wrapped up with a lively panel discussion led by Emeritus President Dr Lock Kai Sang. The career progression pathway a racted par cularly strong interest, with many ques ons from the floor posed to Mr Lee. Following this, all par cipants adjourned to the func on space next door to network over food and drink. Here’s to many more years of friendship with the Dutch!

Ms Vonno then shared briefly about the unique engineering challenges faced in the Netherlands, striking an upbeat note about the poten al for knowledgesharing between Singaporean and Dutch engineers. Echoing their sen ments was the first speaker for the day, Mr Thijs Kamphuis. Drawing on his experiences as a lecturer and project engineer in the oﬀshore wind energy sector, he emphasised the need for CPD and upskilling oneself for greater marketability in today’s rapidly-changing job market.

Ms Margriet Vonno, the Dutch ambassador to Singapore, spoke at length about the poten al for engineering interac on between both countries.

Up next was Mr Tan Kok Yam, Deputy Secretary of the Smart Na on and Digital Government Oﬃce in the PMO. He provided updates on the Digital Government Blueprint, and made some per nent sugges ons on how engineers could keep up with the advancements brought about by Industry 4.0. Ms Pa y Mamola and Emeritus Professor Elizabeth Taylor, who are the Chairperson of the APEC Engineers Agreement and Deputy Chairperson of the Interna onal Engineering Alliance (IEA) Governing Group respec vely, spoke about the various IEA agreements and accords, how these can benefit, as well as their future outlook.

(From le ) Ms Pa y Mamola, Mr Thijs Kamphuis, Prof Yeoh, Dr Lock, Em Prof Elizabeth Taylor, Er. Tan Seng Chuan and Mr Danny Lee pose for a group photo on stage a er the forum.

ADVERTISERS’ INDEX Building and Construc on Authority ––––––––––– Page 01

IES Membership –––––––––––––––––– Inside Back Cover

Cementaid (S.E.A.) Pte Ltd –––––––––––––––––––– Page 05

IES Railway Systems Handbook ––––– Outside Back Cover

IES Chartered Engineer –––––––––––– Inside Front Cover

THE SINGAPORE ENGINEER January 2020

The Singapore Engineer January 2020

Articles inside

Sweden’s biggest road and tunnel project A 21 km motorway bypass is being constructed to relieve traffi c in Stockholm

Winning projects represent supreme global engineering feats The InsƟ tuƟ on of Structural Engineers (IStructE) announced the winners in November last year

Enhancing standard test approach to beƩ er refl ect applicaƟ on requirements PracƟ cal adjustments to the specifi caƟ ons can lead to beƩ er outcomes

ConstrucƟ ng and fi nishing the new Istanbul airport A wide range of chemical products was used in the fi rst phase

Payment Claims - EnƟ tlements and LimitaƟ ons A brief summary of the decision by the Court of Appeal on a case relaƟ ng to the Building and ConstrucƟ on Industry Security of Payment Act, and key takeway points, are provided

The future of infrastructure will be smart With the changing urban landscape, ciƟ es must transform to be more accessible and producƟ ve

Technologies for the diff erent processing stages in asphalt recycling Reclaimed asphalt pavement (RAP), is a valuable resource

Singapore’s construcƟ on demand for 2020 expected to remain strong The built environment sector is urged to look ahead, invest in digitalisaƟ on and innovaƟ on-driven growth, and groom local talent

Thomson-East Coast Line Stage 2 almost complete The 43 km Thomson-East Coast Line will open in fi ve stages starƟ ng from this year