Koersief 101

EDITION 101

January 2017

Structures of Asia

Slimme en efficiĂŤnte constructies voor nieuwbouw en hergebruik

Piekstraat 77 3071 EL Rotterdam T E

010 201 23 60 imd@imdbv.nl

www.imdbv.nl

Editorial

Editorial

3

Dear reader,

Chairman’s note

5

Agenda

7

Asia, the largest continent in the world. A continent with many cultures, civilizations, and also structures. More than 4.1 out of the 7.4 billion people in the world live in this enormous continent. A continent with seven of the ten largest cities in the world. Besides that, nine out of ten of the highest buildings are located in Asia. In China, seven of the ten longest bridges in the world are constructed.

I could continue this list with other interesting top 10 enumerations for pages. Therefore, the editorial board wanted to dedicate an edition of the KOersief to this incredible continent with many astonishing structures: ‘Structures of Asia’.

Theme: Structures of Asia The Petronas Twin Towers Design of one of China’s largest towers Living and working in China Structural design of the Shanghai Tower Structural giants of Asia China’s Hong Kong Zhuhai Macao Bridge Singapore Sports Hub

9 12 16 19 24 27 32

Master’s thesis Jelmer Feenstra

37

FDS-2-Abaqus: An automated CFD fire to FE thermomechanical coupling program

Joey Janssen

40

Cold bent glass fins in a lattice gridshell

KOersief 100 contests

43

KOers Education Update

44

‘In Dialogue With..’

45

Colophon

Of course, the usual features are included as well: an article about the graduation projects of Joey Janssen: ‘Cold bent glass fins in a lattice gridshell’ and Jelmer Feenstra: ‘Research into fire and failure behavior of structures by a coupled fire to thermo-mechanical analysis’. As always, we end with an inspiring column, written by Hans Lamers.

I hope you will enjoy reading this special of the KOersief about ‘Structures of Asia’.

Column Hans Lamers ‘Bitcoin mining’ university

This edition contains articles about spectacular structures like the Sports Hub in Singapore, designed by Arup, the Shanghai Tower by Thornton Tomasetti, the Petronas Twin Towers by Cesar Pelli, and an enormous project from Royal HaskoningDHV: the Hong Kong Zhuhai Macao Bridge. This edition also includes an interview with structural engineers who worked in the Far East.

46 46

On behalf of the editorial board, Thomas van Vooren Editor-in-chief KOersief 101

KOersief 101 | January 2017 | Structures of Asia

3

We’re committed to a sustainable partnership ENCI. The cement for a secure future.

In the construction sector everyone must take on his ecological, social and economic responsibility. ENCI is committed to doing that together with the customer. So we develop sustainable products suited to the economic and ecological realities, and we support a strong partnership. We share experiences and offer solutions. Eco-responsibility means working together for a secure future for the generations to come.

More about our eco-responsible approach at www.enci.nl

Chairman’s note Dear KOers members and relations, First of all, on behalf of the 47th board, I would like to wish you the best in 2017. We hope to see you all during the many activities that KOers will organize this year. In the 100th edition of the KOersief, the 47th board was introduced to you, so this is my very first chairman’s note.

Looking back at the first part of the academic year, it was quite busy, but a lot of fun. Our first activity, together with the 46th board, was a lunch lecture. Two days later, we organized the first event by ourselves: the KOers Introduction Day. During this event, the new and old members of KOers got to know each other and the new board. On the 11th of October, the ‘Nationale Staalbouwdag’ took place, and of course KOers was well represented by all the students that joined us there.

Derk Bos even won one of the Student Steel Prizes!

laminated timber elements (up to 46 meters long!). Also, the ‘Betondag’ was a huge success. This educational day offered us the opportunity to meet companies and learn about new materials and techniques. As a cherry on the cake, Marijn Bruurs (44th board of KOers) won two prizes with his research!

In the end of October, the 100th edition of the KOersief was released with an impressive release party, during which many old board members and editors were present. I can only applaud the KOersief editorial board on this 100 pages thick anniversary edition of the KOersief and on this well organized evening, in collaboration with the 46th board.

Last but not least, I want to thank the editorial board for this 101st edition of the KOersief. I know you will enjoy reading this beautiful edition about Asia.

The first excursion of the year took place in Germany. We visited the production halls of a company that fabricates huge

Lars Croes Chairman of the 47th board of KOers

Yours sincerely, On behalf of the 47th board of KOers,

! l a n o i t a n r e t in s e o g R K B l ! y Peddel padde d a e r s l l i k s e l d d a p r u June o y t e G Cologne 9-11 4 May

Enschede 12-1

KOersief 101 | January 2017 | Structures of Asia

5

Kijk eens goed om je heen, al je medestudenten zijn na je studie

Bouwkunde

jouw concurrenten. Oriënteren en specialiseren tijdens de studie is dus nog niet zo’n slecht plan. Want direct je droombaan vinden na je afstuderen is niet vanzelfsprekend. Met de juiste persoonlijke begeleiding en kennis van de markt helpt Continu jou met die eerste stap in je carrière. Daarvoor zijn we tenslotte intermediair.

Je carrière wacht op je, waar wacht jij nog op?

Ga naar www.continu.nl, vind de vestiging bij jou in de buurt en kom in contact met één van onze adviseurs.

Continu is gevestigd in Almelo, Amsterdam, Arnhem, Breda, Capelle aan den IJssel, Eindhoven, Heerenveen, Maastricht en Utrecht

Elektrotechniek

Civiele techniek

Installatietechniek

Werktuigbouwkunde

www.continu.nl

Activities

Agenda KOers Coffee Time Weekly KOerscorner, Vertigo floor 2, TU/e Every Wednesday during the lunch break, KOers serves a nice cup of coffee or tea. So, allow yourself to have a break and join us on Wednesday between 12:30-13:30h on floor 2.

KOers Coffee Time on floor 9 Once a quartile Vertigo floor 9, TU/e Every third Thursday of the quartile, we will have a special edition of the KOers Coffee Time on floor 9. This is the perfect time to have a chat with your tutor while drinking a nice cup of coffee.

Staalbouwdag

October 11th

Lunch Lecture January 12th Trappenzaal Vertigo, TU/e The lunch lectures will continue throughout the year. The goal is to match the lunch lectures to the courses or show an unknown subject that is connected with structural design.

Next up is a lecture by a technical inspection service, that is involved in many risky projects. An employee of BouwQ will tell us about this unknown field of expertise.

Lunch Lecture Octatube

October 18th

KOers Design Challenge March TU/e A new edition of the KOers Design Challenge is coming up in March. The theme and date will be announced in the near future. Prepare yourself with a competitive mindset!

Release KOersief 100

October 21st

Betondag

Timber excursion

October 28th

KOers Coffee Time on floor 9

November 17th

December 1st

KOersief 101 | January 2017 | Structures of Asia

7

Building the present, Creating the future

Innovatief en duurzaam BAM heeft de ambitie voorop te lopen in duurzaamheid en innovatie. Robotisering, 3D-printers en drones bieden nieuwe mogelijkheden in het bouwproces. Met internet of things, data en virtual reality kan slim worden ingespeeld op de behoeften van eindgebruikers. En wat is het effect van zelfrijdende auto’s op de infrastructuur van de nabije toekomst? De klant, de eindgebruiker en de omgeving staan centraal in ieder project, daarom zoeken wij voor elke vraag een duurzame oplossing. BAM vernieuwt. Jij ook?

Wil je weten hoe het is om te werken bij BAM? Kijk op onze website en social media voor verhalen van jonge BAM-medewerkers en lees wat jouw mogelijkheden zijn: bam.com/nl/werken-bij-bam Koninklijke BAM Groep nv @WerkenbijBAM @WerkenbijBAM

Leidende posities in Nederland, België, het Verenigd Koninkrijk, Ierland en Duitsland.

Wereldwijd projecten in meer dan 30 landen.

Actief in alle fases van het bouwproces.

Circa 21.500 medewerkers.

Stages

Startersfuncties

BAM Graduate Programme

Young Engineers Programme

▸ Meewerkstage

▸ BIM engineer

▸ Vier functies in twee jaar

▸ BAM International

▸ Afstudeeropdracht

▸ Technisch adviseur

▸ Technisch én strategisch

▸ Expat life

▸ Werkvoorbereider

▸ Zelf richting geven

▸ Two-year-programme

▸ Tenderstrateeg

▸ Persoonlijke ontwikkeling

▸ Projectontwikkelaar

Malaysia’s journey into the 21st century

The Petronas Twin Towers By: Thomas van Vooren Editor-in-chief KOersief Perhaps as important to Kuala Lumpur as the Eiffel Tower is to Paris and the statue of Liberty is to New York; the iconic Petronas Twin Towers designed by Cesar Pelli are definitely the symbol of modern Malaysia. These two impressive towers were considered as the tallest building in the world from 1998 to 2004. However, the towers are not simply recognized for their height: it was Pelli’s conceptual effort to incorporate Islamic motives and symbols into the design process that would influence the design and the detailing of the building. Furthermore, well-known by the movie-experts among us, the Petronas towers were the film set of a 1999 movie called Entrapment, starring Catherine Zeta-Jones and Sean Connery. Even though I would really recommend this movie, this article gives you more information about structural design and the construction of this impressive creature.

The Petronas Twin Towers, completed in 1998, each have approximately 21,800 square meters divided over 88 floors as part of the 1.7 million square meters Kuala Lumpur City Center mixed-use development. Their structures consist of high strength concrete columns, core, and ring beams and also steel floor beams and decking to enable an economic and fast construction. The slenderness of the towers and the Skybridge between them required attention to wind behavior and damping, which will be explained later on.

A solid foundation Excavation of the building pit started in March 1993, after developers shifted the whole site 60 meters to the southeast of where it was initially designed to be built. Drilling had shown bedrock irregularities at the site that would have made supporting the immense weight of the building an almost impossible challenge. With its newly fixed site a quick stroll away, a massive foundation was excavated, its 21-meter depth was easily capable of swallowing a five-story building. During excavation, about 500 truckloads of soil were removed every night.

To support a single skyscraper with a weight of 300,000 metric tons is surely an impressive engineering feat, but to pour a foundation that can handle two of such towers required not only a lot of structural knowledge, but also the largest and longest continuous concrete pour in Malaysian history – and this is a country that builds almost everything from reinforced concrete.

Each tower required an immense foundation, comprising a forest of deep piles driven into the bedrock; once the 104 concrete piles supporting each tower were driven into the earth, a 4.6-meter thick concrete raft was poured over them.

For an impressive 54 hours, a truckload of concrete would arrive every 2.5 minutes to pour this massive foundation plate.

From the beginning of the excavation until the completion of the massive foundation one full year had passed. From that point on, the construction of the towers began.

Sky high Originally, César Pelli had the towers topping out at 427 meters, which fell only 15 meters short of tying the current

KOersief 101 | January 2017 | Structures of Asia

9

— � � � � — � � �  � � � ­ Ž �

 � ‘‹ ’ €ˆˆ Š‹‹ ­ ­ ­ � ˆ‹ ‹‹‹ ­ ­ ­ � ƒ …‹ ’ €‡‘‹‹ ­ ­ ­ � ‚‰‹‹ � ƒ ­ � � — �  � ˆ­‚ � €‚­Š  ƒ world’s tallest building: the Sears Tower in Chicago. Once Malaysia’s prime minister found out how close it was, he pressured the architects and engineers to find a way to make the towers taller, so that the world’s tallest building would be in Malaysia.

Although the designers did not add any floors to the structure, they still found a way to push the height over 450 meters, wresting the crown from the United States for the first time since the construction of New York’s Empire State Building in 1931.

In yet another unorthodox decision: the construction of each separate tower was appointed to a different contractor.

And, to make it even worse, both contractors were based in different countries. Japan-based Hazama Corporation led the consortium for Tower One, and South Korean titan Samsung Engineering and Construction led the build team for Tower Two plus the Skybridge: the unique two-level structure that would connect the two buildings at roughly their midpoints.

…­ � •

Figure 2: Typical lower floor plan ˆ‰‰† œ ž “ ­

­ „‚‡ „Š„

Analytical modeling Each tower was modeled in three dimensions using the SAP90 general analysis software, including perimeter beams and columns at all floors, a central column representing the core, and an outrigger beam system from columns to rigid offsets from the core.

Figure 1: Construction of the massive foundation of Tower 1

Thousands of Malaysian and foreign workers were hired for the two construction teams‌ and the race was on! There was definitely a sense of competition to see which team would finish building their tower first, but also whose would be deemed best.

In the end, the competition for the best tower may have ended in a draw, but there is no question about who won on speed. The South Korean team had not only a tower, but also the Skybridge to build, and even started construction a month after the Japanese team. However, the Koreans did finish first, about a week before their rivals.

As the towers steadily reached ever upward, the stainless steel cladding was fitted to the facade, comprising 83,500 square meters of stainless steel extrusions and 55,000 square meters of laminated glass. This cladding was applied to realize Pelli’s vision of the Petronas Twin Towers being a ‘multi-faceted diamond sparkling in the sun’.

Dynamic studies The dynamic properties of the main towers are important for cross-wind effects on the structure and for occupant comfort. The wind behavior of the towers was studied in three ways.

10

KOersief 101 | January 2017 | Structures of Asia

Force balance wind model A 1:400 high-frequency force balance model was used to determine along-wind and across-wind forcing functions for each overall tower. Based on the design wind speed of 35 m/s at 10 meters elevation, wind forces for structural design were determined from the mean and standard deviation of wind forces measured and the dynamic properties of the building.

Aeroelastic wind model The highly articulated nature of the facade may cause helpful aerodynamic damping as the buildings move. The

Notable dates 1993, March 1994, March 1994, April

1995, May

1995, August 1996, February 1996, March 1996, April

Start of the excavation.

Excavation and foundation for Tower One complete; construction begins.

Excavation and foundation for Tower Two complete; construction begins.

Pre-assembled Skybridge arrives from South Korea.

Skybridge is lifted into place.

Topping out of both towers is completed.

Installation of pinnacles for both towers.

Petronas Towers officially declared the world’s tallest building.

twin tower configuration may cause interaction between the towers through cyclic vortex shedding. Analytical procedures and force balance results are insufficient to study such phenomena. A 1:400 aeroelastic model of both towers hinged at their bases simulated along-wind and across-wind tower behavior with critical damping being varied between 1 and 3 percent.

“A multi-faceted diamond sparkling in the sun.�

Results of tower studies Aeroelastic values using 2 percent of critical damping showed slightly reduced base forces at one tower and slightly increased base forces at the other. Because even a slight increase in damping for ’50 year storm’ movements would reduce aeroelastic results, the design of both towers was based on the largest force-balance results for either tower. For occupant response, an inherent damping of 2 percent and a ’10 year storm’ gives peak accelerations at level 87 of 17 to 20 milli-g’s from force-balance tests and 14 to 18 milli-g’s from aeroelastic tests; well within the commonly used 21 milli-g’s guideline for comfortable office occupancy in long-period buildings. Therefore, on supplementary damping, such as viscoelastic pads or tuned ™“ � �“‘ “— �…—• ’ …– …•–�—’ Œ�’ š mass dampers (TMDs) was needed or provided.

year to test and plan, and two weeks to actually perform. In the end it was flawlessly executed.

The response of long, slender, cylindrical bridge legs to vortex-shedding excitation at low wind speeds was of particular interest. Each leg is a steel tube with a diameter of 1.1 meters, spliced by butted bolted flanges. Pairs of legs diverge as they rise from a common lower support point on each tower. All four legs are effectively isolated from the rest of the bridge and the towers by joints of PTFE (teflon) on stainless steel: ball joints at lower bearings, ‘rocker’ and ‘slide’ bearings at box-to-girder support pad, and a ‘pin-in-globe’ bearing for lateral leg restraint at box midpoint.

 ›

Figure 4: The finishing touch of the Petronas Towers

The crowns Finally, the time came to set the crowns on top of these twin towers. These crowns were gleaming 73.5 meters tall stainless pinnacles, which had been redesigned to bring the building’s official height to 451.9 meters above street level.

From that moment in 1996, the Petronas Towers were the tallest building in the world until 2004, when the Taipei 101 took over the top spot followed by the Burj Khalifa in 2010.

Figure 3: Skybridge elevation and details

Interestingly, by the time Malaysia discovers whether or not it will achieve its stated goals in the year 2020. The Petronas Twin Towers will not even be in the top ten tallest buildings due to the rapid advancing construction technologies. In fact, the expectation is that the Petronas Towers, once the tallest in the world, will rank at 27th place by 2020.

The Sky bridge ‚ ˜ ’ Š

The ultimate highlight of the Petronas Towers is the Skybridge, the two at their

41 st

which connects

buildings

References:

and 42nd floor.

This bridge holds the world record of highest [1] Merchant, C. (2016). ‘The History and construction of the two-story bridge in the world and spans a distance of 58 Petronas Twin Towers’ Available on December 3rd, 2016, Source:  �� meters. A complex system of hinges, expansion joints, http://www.expatgo.com/my/2013/01/09/the-history-and� � � � �  ­ �

€

Â? construction-of-the-petronas-twin-towers/ and spherical bearing ensures that the Skybridge stays in

‚ ­ [2] Thornton C. H., Hungspruke U., Joseph L.M. (1997) ‘Design of the place, regardless of how the two individual may

� ƒ

towers

„

… � world’s tallest buildings – Petronas Twin Towers at Kuala Lumpur independently move or twist.

City Centre’.

† …

‡ ˆ ‰ €

Š

Figures:

„ ‚ ‹ A very demanding task was lifting the prefabricated

Header,

Merchant, C. (2016). ‘The History and construction of

Skybridge into its final place. Therefore, a specialized 1, and 5 the Petronas Twin Towers’ Available on December 3rd, 2016, Sourcehttp://www.expatgo.com/my/2013/01/09/  ŒŽ ‘  ’…“Œ �’”…•–�—’ engineering firm was brought to manage the lift of the the-history-and-construction-of-the-petronas-twin… Š

– including

Â?

€�

450-tons assembly the 325-tons main structure

towers/

… � � � � Š 2-4 Thornton C. H., Hungspruke U., Joseph L.M. (1997) ‘Design as well as the support legs and other equipment – over 170 of the world’s tallest buildings – Petronas Twin Towers at ­­� œ

– Š the ž ’

Â?

meters above ground.

The nine-step process took over a  Â&#x;›¥  ­­Â? Kuala Lumpur City Centre’.

KOersief 101 | January 2017 | Structures of Asia

11

Dialogue between architects Mark Hemel, Barbara Kuit, and structural engineer Arjan Habraken

Design of one of China’s largest towers Interview with: Mark Hemel, Barbara Kuit, and Arjan Habraken Co-founders and directors of IBA, TU/e lecturers

By: Denise Kerindongo & Tom Godthelp Editors KOersief

The Canton Tower is one of the largest towers of China and a 600 meters high landmark in Guangzhou. Being the architects of the Canton Tower, a hyperbolic super skyscraper, is special. Nevertheless, the fact that both architects, Mark and Barbara, work at the TU/e as well as Arjan Habraken, who was involved in the structural design, is even more special.

This was the reason for the editorial board of the KOersief to organize a dialogue between the architects and structural designer about their collaboration and the design process of the Canton Tower.

How did you start with the design of the Canton Tower?

Barbara: The project started during the advance of the Olympic Games in China. We heard about the competition that was held because of the organization of the Asian Games. The competition included the urban design of an area with a landmark as a main subject of the design; a television tower. Mark and I applied for the competition and submitted our work. Luckily, we were chosen among other groups to design the tower. This was in direct collaboration with Arup; they initiated to do a project together. In this way, the collaboration started.

The assignment was to make a masterplan for the whole plan area and a tower with unlimited height. The only demand was that the new tower had to be higher than the existing television tower, which was 350 meters tall, and that the project would stay within budget. Mark and I were free in our design. Right from the start, the project seemed very interesting and appealing, so we immediately wanted to enter the competition.

on the designs that were made. These three chosen tower designs were completely different. The first design was simple and straight, the second design was cylindrical, and our design was slender, hyperbolic, and twisted. Our design was poetical and was meant to have an impact on the city.

Could you describe the design process?

Barbara: At the beginning, a certain amount of time was given to complete the job. In the first phase, 15 offices were chosen, who all needed to do a submission. From those 15 offices, the number of offices was reduced to three, based

Barbara: In the second phase, more elaborate submissions had to be presented. Ultimately, Mark and I were chosen for the competition, which was a trajectory of about one year that was sometimes a bit frustrating. At first, we personally invested a lot of which you did not know whether you would

12

KOersief 101 | January 2017 | Structures of Asia

Arjan: From Arup’s point of view, the design had to be based on strong arguments. Later, we would decide whether the project was achievable or not. This was an important aspect for the ultimate decision. Since other research was conducted on the achievability while designing the tower, the design had a good chance of winning the competition.

This research was carried out by Information Based Architecture (IBA) and Arup and was about, for instance, the different construction methods. We hoped that this would prevent unwanted surprises. The main role of Arup, at the beginning, was to make sure that the design actually could be built when looking at the structural design.

7 1

7

Pearl River Delta

7

1

1

7

1

7

7

1

7

1

1

7

10

7

1

7

1

0.5m

7

1

1

max

60

Shear diagram 1m rings 0.5m diagonals

20

N

1

1

1

1

Tapering towards the top

Rotation of vertical elements to create tightening

1

1

1

1

1

1

1.5m

1 max Moment diagram

Round tower

Elliptical section

Twisting of the top of the tower

Densification of rings according to shear

Rotation of rings according to shear

Diagonalization of nodes into a stiff structure

Specific areas of diagonalization in opposite direction to stiffen waist

Materialisation of vertical elements according to moment

Materialisation of rings and diagonals according to shear

STRUCTURAL MORPHING

Figure 1: Structural morphing

get something in return, so this was a large risk. However, once you have invested a lot of time in the project, your only wish is to keep improving the design, so we put all our efforts and resources in the design.

The client kept asking for more and more, because it was not clear which design team would be chosen. Besides, it was not clear whether the design would fit the budget.

This meant that the realization of the tower was not only uncertain for us, but also for the client. The whole concept was something new which had never been built in China; this meant that certain rules did not exist, due to the fact that most buildings only reached a certain height. Some other aspects also needed to be worked out while we were working on the project. This made the project much fun, but also very difficult because it was uncertain for all parties. So, all this led to a very intense start of the project.

What is the concept behind the architectural and structural design?

Barbara: The demands for the design concerning our vision were that the tower needed to be as transparent as possible and also that the tower had a certain waistline. It could be compared to a female dancer who was dancing at the river.

We wanted to incorporate a female shape into the design.

The initial waist of the building was only 13.5 meters. The fact that the tower was so slender in the middle appealed the client. At the same time, the challenging part was to

Arjan Habraken Structural designer and founder of SID Studio, TU/e lecturer.

Arjan Habraken has studied civil engineering at the Delft University of Technology and graduated at the Department of Mechanics & Constructions in 1996 with an honorable mention from the Dutch Concrete Association.

During his career, he worked on many high-level, international projects. He is an experienced project manager and design leader, not only in concrete and steel structures, but also in glass, cable, and membrane structures. He has extensive leadership experience from his function at Arup, for instance, as a group leader of the construction department and his

optimize the required amount of columns and to keep the slenderness in the middle. The images in Figure 1 were used in the competition to explain how the desired shape was established and which conceptual steps were made in order to obtain the shape.

Arjan: There was a search for a certain shape of the tower.

However, which aspects could be changed to create a certain direction in the tower and what aspects needed to stay? This question became leading in the design program.

With six formulas, the form was created starting from a tube with rings.

All steps were designed parametrically in order to do research for the slenderness (Figure 1). This became a whole trajectory on its own. With a few parametric changes, the output could be seen rapidly. This helped to integrate the architectural and structural design.

Barbara: One certain thing was that a twist needed to be made, because straight columns were used. Right away, with the help of elastic bands and circles, we researched the different possibilities. However, that did not result in the desired form. So, we examined elliptical shapes instead of circles, two ellipses of different shapes, and other aspects. The next step was to determine whether the elastic bands needed to be woven straight up or with a slope. By constantly changing small parts of the design, we

participation in the office management team. With this function, he was involved in the initial structural design of the Canton Tower during the competition phase.

His interest in architecture and lightweight structures was a prominent motivation to launch SID Studio. His focus lies at design work and the cooperation with architects, resulting in extensive structural and architectural integration. This to raise the level of structural shaping to support the aesthetics and the function of the project.

His position as Assistant Professor at the Built Environment department at Eindhoven University of Technology supports this vision and strengthens the relationship between practice, new developments and research. He is currently running two Master studios on ‘Adaptive structures‘ and ‘Form and Material Optimization‘.

For more information, please visit: www.sidstudio.nl

KOersief 101 | January 2017 | Structures of Asia

13

Figure 2: Canton tower close-up

established control over the end result. This control helped to determine whether the design was realistic and could be built or not.

Arjan: This control was also very important from a structural designing point of view. If you control the design, there is also control towards the structure. When looking at the execution of the tower, all nodes could be computed parametrically. With the help of numbers, much could be described because there was a clear starting point. If the shape was much more complex, all nodes had to be calculated separately which would make the design much more difficult. The basis already had a clear structure which was taken through the whole traject.

Barbara: Immediately after the competition was won, the client wanted a rotating restaurant at the top of the building, which is typically Asian. Sometimes, the view in the restaurant is outwards and sometimes the view is directed to the inner construction. This gives spectacular views and creates an extra dimension. In addition, we had a wish for a panorama elevator through which the people could actually see what kind of building they entered. The architecture and

Shanghai Tower facts Architect: Information Based Architecture

(Mark Hemel & Barbara Kuit) Structural engineer: Ove Arup &

Partners Hong Kong Ltd. LDI: Guangzhou Design Institute Client: Guangzhou Construction

Investment & Development Co, Ltd, Guangzhou TV station General • Gross floor area: 114,000 m2 • Height: 600 m • April - August 2004 First Place in Invited International Competition • November 2005 Ground breaking ceremony • October 2010 Opening

14

KOersief 101 | January 2017 | Structures of Asia

the structure of the tower are woven together very tightly.

At a height between 170 and 300 meters, a skywalk is situated: here are no floors, but with the stairs, you can go upwards or downwards. The skywalk passes the most slender part of the tower, the inner rings can be touched from this location.

How did the communication go between the involved parties?

Barbara: At the start, we had a collaboration with Arup Amsterdam. It was unknown how the tower would react to wind loads due to the tower’s complicated external open structure. Therefore, Arup London was brought into the design and later Arup Hong Kong made the final structural design. This was because the office in Hong Kong was closer to China and their local knowledge was needed. A collaboration between the different Arup locations always existed, but it slowly shifted to Arup Hong Kong.

Arjan: Every once in a while, there was a meeting to present the different design alternatives. Separate studies were made to optimize the shape and, afterwards, the parties came together to discuss the results of the studies. There were certain fundamental ideas and from those ideas, we decided which one was the most important in order to make a decision for the best shape.

How was the construction organized?

Barbara: It was not clear from the start how the tower would be constructed, resulting in the examination of different possibilities. Later on, we determined how the outer and inner parts would be connected. One thing that was clear from the start, was that two different illustrations of the building would exist; one from the outside and one from the inside. From the outside, the columns are more noticeable, and from the inside, the rings, which do not lay in the same plane, are more noticeable. These rings are connected to the columns from within and in between these two, the diagonals are situated. From the inside, the rings form the space, and from the outside, the columns form the space. This results in two different perceptions of the building.

Arjan and Barbara: There was a need for a material with a high strength which also could be designed transparently, so we chose a steel structure. The columns are tapered towards the top, but still follow a straight line with the other columns. There is no visible change in distance between the columns.�

How is the structural stability ensured?

Barbara: The inner part and outer part interact. This interaction between the concrete core and external steel is possible by means of steel connections every few meters (Figure 3). The external steel plays the biggest part in providing the stability, but we tried to optimize the material used for the stability. At first, the core was more slender, but due to the amount of cables and the elevator that needed to be placed, the core became bigger. However, the core is not oversized.

At first we started with a rectangular core which evolved into a circular and later into an elliptical core, which was the best form for a lot of other aspects (elevators, stairs, cables, fire resistance, etc.). The leading factor for the dimensions of the core was the waist of the tower. An interaction existed between the demands that the waist needed to have a certain slenderness, and that the core needed to fit into this. In addition, the elevators needed to lead to the center of the rotating restaurant and fit into the core. Those three aspects were the variables of the design of the core. From the geometry and all demands, a certain core was designed.

Afterwards this core was structurally optimized.

Figure 3: Inner view of the structure

Figures: Header, 1-3

Mark Hemel & Barbara Kuit / Information Based Architecture, Amsterdam

www.octatube.nl

Mark and Barbara tell their story

Living and working in China Interview with: Mark Hemel and Barbara Kuit Co-founders and directors of IBA, TU/e lecturers

By: Caroline Koks & Tom Godthelp Editors KOersief

To be able to monitor and coordinate the design process of the Canton Tower, Mark and Barbara lived in Guangzhou, China a while. Below, they tell their inspiring and informative story, especially for people who think about living and working in an Asian country for a while.

What are your experiences with working in China?

Barbara: For me, it was a completely new experience. The process of decision making in China differs a lot from Europe.

In Europe, a lot of parties are heard during many meetings, which results in a lengthy process. Although the present parties in China are even bigger, the meetings are much more structured and have a short duration because decisions are made quickly. In addition, this organization structure makes it difficult to get something done when you disagree about a subject. For example symmetry: in China, symmetry was a really strong quality at that time, but we did not want symmetry in our plan. We convinced them, when Mark used a picture of a Chinese model to show, that a face is not symmetric either.

Besides the asymmetric design, the tower is also rotated about its axis. Although this results in one side being more attractive than the other side - which looks less slender because of the rotation - Mark managed to sell the design.

Another nice thing of the participation was that everything in China goes with a particular urgency. However, this was only the case after the announcement that we had won the contest. Before that, we were in a very uncertain period.

In the contest-phase, we had several appointments with

Figure 1: Shenzhen-Zhongshan bridge tunnel-link

16

KOersief 101 | January 2017 | Structures of Asia

the costumer within a week with travel and subsistence allowances for own account. The other participators of the contest had the same appointments during that week and nobody knew whether they were in the preferred position or not. After that week, we did not hear from them for a long time. The only thing we knew was that we had spent a lot of time on this project and we really wanted to realize it.

Mark: In China, they work step by step. This is also necessary for the order, because a lot of participants were present during the meetings. At a certain moment, I stopped booking returns, because the programmes changed everytime. You start with the first meeting and when everybody agrees with the main subject of that meeting, the next meeting is planned. This means that everytime a higher level is reached.

You do not know what is next, so you do not know what you are waiting for. The issue was whether they wanted me to stay for further explanation or not. I might not call this chaotic, but incemental. You first meet with the people who directly matter and after that, the follow-up meetings will be planned.

You need to adjust to their schedule.

Was it hard to get used to the Chinese culture?

Mark: It was hard, but I think we had a big advantage, because of our age and the fact that we had a very open mind. We were able to adapt, since we did not have a ‘standard’ during that period. This was our first big project, so everything was new for us anyway and adjusting was evident.

Compared to the smaller projects we did before, it was hard to keep track of everything and stay in contact with everyone.

In the first place, we had a design team with Arup, which is in itself quite big. Then you have the client, who hired some experts to look after the whole proces and then there are people who are watching in the background, like PhD’s etc.

You especially have the control within your own team. We, as architects, designed what we liked and the engineers were checking if our designs were possible. An overall control is missing, because you are just part of a whole. Besides our ideals and all the requirements of the structure and building services etc., the client has his wishes as well. You are definitely not in the coordination position as an architect.

There was even a local designer present, but we noticed we had more influence as Westeners. Despite this, I felt helpless most of the time. You would like to tell how you want to execute everything, but that is not how it works.

Do you have more control over an European design team?

Mark: In smaller projects, I think that it is clear that you control the design proces, but in larger projects, also in Europe, you have a lot of contradictions within a team. I think

it is all a little more extreme in China than here and you have even less to say. In retrospect, it was a miracle that a lot of our ideas are realized. A funny fact is that the client is on your side most of the time. The greater part of the discussions are about responsibilities like safe structures, sustainable building services, and of course costs. However, in the end, the client wants a nice, as slender as possible design. We, as architects, are responsible for that. In a big project, you experience different similarities with different parties, but with the client, we accomplished the most.

Did you have any experience with high-rise buildings and what is your opinion about the growing amount of high rise buildings?

Mark: We did not have any experience with high-rise buildings, but we saw that as an advantage. We were able to have a fresh look on the project. I think that the increasing number of high-rise buildings and the related spatial densification on its own is a good development, because it results in a so-called ‘cross-pollination’. A dense way of living results in a more sustainable society, because people do not have to travel long distances between their homes and work, for instance. On the other hand, the designs of highrise buildings can be much more diverse. You see a lot of office blocks with full glass facades. This trend started in the era of modernism and this – in their opinion ideal - has just been copied and copied. There should be a bigger variation in the high-rise buildings alongside the reflecting, isolating objects. In the design of the Canton Tower, for instance, the structure is designed on the outside of the building. The glass

is not reflecting in this way and we did not have to pack the structure to protect it against fire load. Besides, the heat load in the building decreased a lot. I think buildings look better when they are under construction and the structure is still visible. In the Canton Tower, the structure is still visible, and I believe that it brings the object to life.

Another great aspect of high-rise buildings and the large project process is the time for research. Optimization takes such an effort, that you will get the time to develop. You are able to focus on one ingredient and elaborate it into detail.

Designing becomes researching. We are currently working on a large project, and again it is all about collaboration. Which is exactly what we, as IBA, like to do; collaborating and thus learning new things and exploring new paths.

Did you stay in China after the completion of the Canton tower?

Barbara: The completion of the exterior took place in 2010, because of the Asian games. Alongside the exterior, only the upper ring and the core were finished, but the floors and interior were still missing. It took two more years to complete the design. During that period and a while after that, we lived in China. Right now, we are working on a competition in China; the ‘Shenzhen-Zhongshan bridge’, which will connect the two major cities on the Pearl River Delta (Figure 1). The link consists out of a cable-stayed bridge, a suspension bridge, and two tunnels. A tunnel over the full length would be more logical on this place, but they want to create a sort of gateway in China. This design competition is in collaboration with the TEC (China’s Hong Kong Zhuhai Macao Bridge (page 27-30)).

‘progressive’. It constantly attempts to extend the boundaries of artistic design, while also introducing the newest digital technologies. IBA is currently based in Amsterdam, the Netherlands. The design of a 180-meter tall skyscraper in Guangzhou is recently added to their contract portfolio.

Mark Hemel and Barbara Kuit Co-founders and directors of Information Based Architecture, TU/e lecturers Mark Hemel and Barbara Kuit are the co-founders and directors of Information Based Architecture, and graduates of Delft University of Technology. Information Based Architecture (IBA) was originally set up in London, in 1998, as a partnership between architects Mark Hemel and Barbara Kuit. Using the newest technologies, the practice challenges conventional thinking and seeks to exploit new opportunities to enrich our cities with conceptually interesting, and well thought-through environmentally responsible architecture.

The practice specializes in large-scale architectural and urban projects. Having won several high profile competitions, the most famous one being the design for the Canton Tower. IBA can be characterized as both ‘experimental’ and

Mark Hemel worked for Zaha Hadid and taught at the Architectural Association in London, where he was Unitmaster and a design tutor in the Environment & Energy Program. Mark also taught at the Architecture Academy in Rotterdam. Today, he teaches Architectural Urban Design and Engineering at the Built Environment department at the Eindhoven University of Technology. In 2003, he received the RIBA Bronze Medal tutor award from the Royal Institute of British Architects. Mark’s writings are widely published.

Recently he has written a book on the design process of the Canton Tower called Supertall, the rise of bio-intelligence.

Before setting up the practice IBA, Barbara Kuit worked as a local architect on projects of Philippe Starck in London (the Sanderson and St. Martin’s Lane hotels), and subsequently worked for several years for Zaha Hadid on many projects, among which the Mind Zone in the Millennium Dome, London, the Contemporary Arts Center in Rome, Wolfsburg Science Center in Germany, and on many other competitions and projects. Besides IBA, she teaches together with Mark at the Built Environment department at the TU/e.

For more information, please visit: www.IBA-bv.com

KOersief 101 | January 2017 | Structures of Asia

17

Is it easy to combine your work at the university with your work for IBA? Mark: It inspires a lot to combine both. Teaching keeps giving you new insights, both work related as not work related. Practically, it is not always easy, because you need to switch mindsets between office and university work. It is only getting complicated during periods when far traveling is necessary, like the Canton Tower project. Besides being away from home a lot, you are suffering from jet lags.

What was the hardest part of working in China?

Mark: The language was definitly the hardest part. You are always too late when you want to say something because of the delay of the interpreter. First, you need to wait until someone finishes his sentences until you can transfer your thoughts to the interpreter. Then she starts to translate and speaks out your mind. But during that time, the others will keep thinking further, so it is not always relevant anymore what you have in mind. Besides that, you also have the issue that the interpreter not always wants to translate your exact words, due to the culture differences. This can be an advantage, because you are not always aware of their values and principles. This is hard, because you want to stay true to yourself, although you are in a different culture. The interpreter actually changes your ‘own-being’.

The encouraging thing was that I was familiar with the interpreter, because she was one of my former students.

She is from Hong Kong and speeks both Cantonese and Mandarin. She knew the culture and I just needed to rely

on that. I noticed that in the West rationalism is the most important; in China they have more of a holistic approach.

What matters is the overal value including the relation to the context.

What is the advice you can give to students and structural designers who are willing to work in China?

Mark: My advise would be to learn Chinese. After all these years, we are able to follow conversations, but we cannot express ourselves. In contrast to ourselves, our three children are indeed able to express themselves in the Chinese language.

What is the role of structural designers in international contests?

Mark: The architects are the ones that subscribe to a contest when the focus is on building projects. Subsequently, they approach the engineers for a collaboration. When the contest is about civil projects, the engineers are the first participants and the architects will be approached.

I think that a clear integration between architecture and engineering is the most important part. An idea only becomes a design when a harmony is reached between the disciplines. Otherwise, one discipline is subordinate. It is essential to have a natural collaboration from the beginning to reach harmony.

Figures: 1 Mark Hemel & Barbara Kuit / Information Based Architecture, Amsterdam

KIJK OP ONZE WEBSITE VOOR VACATURES

Ontwikkeling - Engineering - Onderbouw - Bouwpartner

www.B-invented.com

A closer look on how to build a 632-meter tall tapered skyscraper

Structural design of the Shanghai Tower By: Tom Godthelp Editor KOersief With a height of 632 meter, the Shanghai Tower is the tallest tower of China, the second tallest tower in the world, and a vertical city facilitating a variety of functions including office space, a luxury hotel, and an observation deck. The shape of the tower shows a beautiful integration between the architectural and structural design, in which a sophisticated structural design enables the creative architectural design. However, to be able to build the Shanghai Tower, several ingenious strategies were developed that are discussed in this article.

Origin and architectural design The Shanghai Tower is located in the new financial center of Shanghai, China; an area that used to be farmland and has rapidly been transformed into a financial area over the last two decades (Figure 1). This transformation is spurred by Chinese economic reformations and required new planning and design strategies to address the need for high density development. Gensler, the responsible architect, incorporated the high-density development in the tower by means of a vertical city concept. For instance, sky

gardens are created every 12 to 15 floors to create a sense of community. These sky gardens are located between the inner and outer skin of the building at the floors above the mega frames, which will be discussed later. The transparent outer skin forms the outer shape of the building and acts as a temperature buffer between outdoor and indoor. In fact, the entire tower is wrapped by this transparent second skin allowing the conservation of energy by modulating the temperature within the void: in the winter, cool air is heated up and in the summer, hot air is dissipated [3].

Figure 1: Transformation of Shanghai from 1991 (left) to 2016 (right)

KOersief 101 | January 2017 | Structures of Asia

19

The super columns are composed of specially designed steel profiles that are covered and filled with concrete to increase the fire resistance and mechanical strength. All beam to super column connections are encased in concrete as well to ensure a proper and stiff performance of the complete structure. The four paired super columns are placed at each 45-degree axis and partly support the outriggers. To decrease the span between these columns near the base, four additional super columns are added to reduce the span from 50 meters to 25 meters (Figure 4).

Figure 2: Aerodynamic design in the wind tunnel

The tower is exposed to typhoon-level wind loads and the shape of the tower is therefore designed in cooperation with the engineering firm Thornton Tomasetti, which made the complete structural design, as well as the aerodynamic design. To reduce the wind load on the building, the shape of the second skin is aerodynamically optimized in a wind tunnel (Figure 2) and with a computational fluid dynamics model.

After testing multiple models, a rotation of 120 degrees between the bottom and upper plan was found to be the optimum (Figure 3). In addition, methods such as softening corners, tapering the shape along the elevation, adding setbacks, varying cross section, adding spoilers, and porosity in the building provided a saving of 58 million dollars of construction costs.

Figure 4: Structural system with all super columns and mega frame under construction near the base of the tower

In addition, a two floor tall mega frame is added between all the super columns every 12 to 15 floors, which divides the tower into nine zones. At the interface of the adjacent zones, space is created for refuge safety areas and mechanical plus electrical plumbing equipment. These floors, located between and on top of the mega frames, span from outer to inner skin and support the vertical weight of 12 to 15 floors of facade. The main task of the mega frames is to provide lateral resistance in combination with the core, outriggers, and super column system. Furthermore, intermediate steel columns are supported by the mega frame. The mega frame is constructed as a double belt truss of structural steel.

The stresses in most of the structural members are in the elastic range; however, the link beams in the core wall exhibit fully plastic deformations but do not exceed the limits set by China’s building code.

Figure 3: Plan rotation of 90° to 210° with the optimal shape of 120°

Structural Design The structural design of the Shanghai Tower faced many challenges such as typhoon-level winds, an earthquake active zone, and a clay-based soil (river delta). The solutions that are found to overcome these challenges are listed in the rest of the article and divided by structural part or system.

Stability and main construction The structural parts of the tower that provide stability, and thus resistance against lateral and vertical forces, are a concrete core that interacts with outriggers and four paired super columns. The concrete core covers an area of nearly 30 square meters and forms the heart of the structural system. To facilitate outrigger connections and to resist extreme bending moments, the concrete core had to be partly reinforced with steel beams and plates in addition to traditional reinforcement. This composite reinforcement method is frequently used in high-rise and especially in super-high-rise buildings.

20

KOersief 101 | January 2017 | Structures of Asia

Software and earthquake resistance Since the site of the tower is located in an earthquake active zone, the non-linear (plastic) structural behavior, especially the behavior of connections of the main joints, had to be determined. The finite element program Abaqus was used to perform the tests on the (composite) three-dimensional

About the structural engineer Shanghai Towers’ engineer Thornton Tomasetti provides engineering design, investigation, and analysis services to clients worldwide on projects of every size and level of complexity. Projects include the structural design of (super) high-rise structures, stadiums, innovative structures, and structural forensics of collapses. Thornton Tomasetti is an independent, employee-owned firm of 1,200 engineers, architects, sustainability practitioners, and supports professionals collaborating from offices across North America and in Asia-Pacific, Europe, Latin America, and the Middle East (Thornton Tomasetti, 2016).

Shanghai Tower facts Architect: Structural engineer:

Gensler Thornton Tomasetti

General • With a height of 632 meters, the Shanghai Tower is the tallest tower in China and at the time of writing the second tallest tower in the world.

• The floor space covers 380,000 square meters spread over 124 floors (above grade).

• 14 percent less glass was needed for the skin compared to a square building with the same floor space.

• Afforded by modern digital technology, mass customization allowed the production of 7,000+ unique glass skin panels on a total of 20,589.

• The elevators in the building can reach speeds up to 64.8 km/h.

• The program of the tower facilitates office space, a luxury hotel, entertainment, retail, and cultural venues.

• The construction costs are 2.2 billion dollars.

Green strategies • The tower has its own power facility providing heat and electricity to the low zone areas.

• External light of the tower is powered by 270 wind turbines, built into the facade.

elements and to prove that the structure is able to withstand extreme dynamic loads and meet China’s Seismic Design Code.

Both steel and concrete elements of the composite structures were modeled in Abaqus. The steel elements were modeled as beam elements and the concrete elements as shell elements. Since M-N-θ (moment, axial force, and rotation) profiles could be determined from the Abaqus models and the soil conditions were known, the total lateral deformation of the tower could be determined.

• The double facade provides an insulating blanket for the tower, which saves energy.

• Water treatment plants are added in the tower to recycle grey and storm water for irrigation and toilet flushing, resulting in reducing 38 percent of water consumption. The plants are located at efficient places, by which pumping energy is reduced.

• The energy required for transporting energy is significant in super-high-rise buildings. By means of the vertical city concept, the nine stacked 12 to 15 story buildings are served by a central utility infrastructure, which allows for substantial reduction in energy transportation.

• 21 percent of the total energy use is saved by 43 sustainable technologies.

Structural • The foundation slab of the tower has a depth of 6 meters and was poured during a 63 hour pour, in which 61,000 cubic meters of concrete was pumped.

• The 120-degree turn from base to top saved 58 million dollars of structural costs due to the decreased wind load on the structure.

• A tuned mass damper of 1,000,000 kilograms, which is placed near the top of the tower, improves the comfort of occupants by means of reducing the sway.

magnetic field and automatically counteracts the weight’s motion and further amplifies the damping effect.

The Shanghai Tower is the first skyscraper in the world that uses Eddy-current dampers. Air sickness of inhabitants will be prevented with this mass damper.

The outer skin The cam-shaped outer skin is comparable to the shape of a guitar pick (Figure 6) and decreases wind loads on the main structure as mentioned before. Nevertheless, the skin of the tower is sometimes exposed to typhoon-level wind

Foundation and lateral deformations The site of the Shanghai Tower is located in a former river delta with a clay type soil in the upper layers. This results in foundation bore piles with a diameter of 1 meter and a length of 52 to 56 meter to be able to reach the bedrock. A 6-meter-deep foundation slab connects the 947 bore piles to the tower. This results in a stiff foundation, by which the total horizontal deformations (drift ratio) of the tower are in either axis less than 1/130 in any direction. This meets the limit of 1/100 specified in China’s Building Code.

However, to reduce the deformation of the tower at the top and to improve the comfort of inhabitants, a 1,000 ton mass damper is added in the top of the tower. This damper acts as counterweight by ‘pulling’ the tower in the opposite direction when the building sways (Figure 5). A so called Eddy-current damper is used to stabilize the weight. This damper uses magnets to provide active damping control.

These dampers are easily adjustable when vibration frequencies change. The iron weight induces an electrical current in the damper that, in turn, creates an opposite

Figure 5: 1,000 ton mass damper tuned by means of Eddy-current dampers

KOersief 101 | January 2017 | Structures of Asia

21

25°

60° 60°

Figure 6: Geometric design and concept of the towers’ external shape

loads. These loads have to be transferred via the space between the first and second skin, which requires additional structures.

Non-sway compression or tension bars are attached to special joints and bridge the space between the inner and outer skin to transfer the wind loads to the stability system of the tower (Figure 7). Special joints between these bars must allow for different temperature deflections, which is possible by means of ‘flexible’ expansion joints that are designed to cover both functions. The structure of the outer skin is created by cam-shaped hoop rings that taper and rotate 120 degrees from the bottom to the top of the tower creating the unique and aerodynamically height accenting shape.

commerce destination; however, the tower is not yet completely open at the time of writing.

The tower today The construction of the tower began in November 2008, after which the observation deck on the 121st floor opened in July 2016. At the time of writing this article, most stories of the Shanghai Tower are closed. It is unknown when the complete tower is scheduled to open, but a fact is that the Shanghai Tower is a soaring symbol of China’s economic future.

Conclusion The iconic shape of the tower anchors the tower as Shanghai’s landmark and represents a new era of creating vertical cities. Cutting edge developments in technology have helped the designers to face the tremendous design challenges and have let them explore the boundaries of super-high-rise design. With the Shanghai Tower, Shanghai’s financial area is becoming one of the world’s foremost

Figure 8: The tower section, construction, and skin during/after construction

References: [1] Xia, J., Poon, D., Mass D. C. (2010). Case Study: Shanghai Tower.

CTBUH Journal.

[2] Zhao, X., Ding, J. M., Sun H. H. (2011). Structural Design of Shanghai Tower for Wind Loads. Architectural design & research institute of Tongji university (Group) Co., Ltd., 200092, Shanghai, China [3] http://www.thorntontomasetti.com/about/ [4] Gensler/Shen Zhonghai, Blackstation, Courtesy of Arch Record [5] http://www.autodesk.com/gallery/exhibits/currently-on-display/ shanghai-tower [6] http://www.slideshare.net/SanskritiJindal/shanghaitower-40930153 [7] SINELAB (April 2015). How your world works - Architecture. Popular Mechanics

Figure 7: Atrium between inner and outer skin

22

KOersief 101 | January 2017 | Structures of Asia

Figures: Header, 1, Gensler/Shen Zhonghai, Blackstation, Courtesy of Arch 3, 4, 5, 7, 8 Record 2 http://www.autodesk.com/gallery/exhibits/currently-ondisplay/shanghai-tower

GRATIS vaktijdschrift Bouwen met Staal

abonnement voor studentleden KOers 04 16 250

BOUWEN MET

STAAL

WOON-WERKGEBOUW TIMMERHUIS, ROTTERDAM

Vakwerk met vierendeelliggers Al vrij snel was duidelijk dat ‘de wolk van staal en glas’ een bijzonder staalskelet zou krijgen. Opgebouwd met vierendeelliggers die uitkragingen tot wel 20 m bereiken, ging het modulair opgezette Timmerhuis vergezeld van een risicovol ontwerpaspect. Behalve extra toetsing en speciale aandacht voor robuustheid van de hoofdopzet, bleek ook de detailengineering omvangrijk en complex.

Onder meer doordat krachten in de knopen bepaald moesten worden uit allerlei belastingsituaties, zoals de uiterste grenstoestand, de montagefase en alle verschillende situaties in een tweede draagweg. Als klap op de vuurpijl is het project volledig stempelvrij uitgevoerd. ir. R.M.J. Doomen

6

AUGUSTUS 2016 | BOUWEN MET STAAL 252

BOUWEN MET STAAL 252 | AUGUSTUS 2016

7

vakblad over staal en staalconstructies

Geef je op voor een jaar lang een gratis proefabonnement op het vaktijdschrift Bouwen met Staal. Ga naar de website www.vakbladbouwenmetstaal.nl en klik in de menubalk op ‘abonneren’ en ‘studentenabonnement’.

Vul daar je naam, adres en studienummer in. Je krijgt dan vanaf het eerstvolgende nummer zes edities in de brievenbus.

Nieuw is, dat studentleden van KOers ook daarna het vaktijdschrift gratis kunnen blijven ontvangen. Geef je daarvoor vanaf nu op via de intekenlijst bij KOers.

Tot je afstuderen ben je dan gratis studentlid van Bouwen met Staal.

Bouwen met Staal Louis Braillelaan 80 2719 EK Zoetermeer tel 088 353 12 12 info@bouwenmetstaal.nl www.bouwenmetstaal.nl

Structural gi Li Guohao Born in Guangdong, China in 1913. Guohao studied at TH Darmstadt in Germany from 1937 until 1940, in which he completed his doctoral dissertation within one year entitled: ‘Practical calculation of suspension bridges with second order theory’. Publication of this study earned him the name ‘Suspension Bridge Master Li’. After the Second World War, he returned to China to become professor at the Tongji University. Guohao participated in several famous bridge designs and constructions such as Chengdu-Kunming Railway Bridge and Nanjing-Yangtze Bridge. In 1973, he wrote ‘Torsion Theory of Spar-Truss Bridge Torsion, Stability and Vibration‘. This book of several hundred thousands of words provided a reliable basis for truss bridge design and construction. Guohao passed away in 2005.

Photo: Nanying Yantze River Bridge (Nanjing, China)

Photo: Penang Bridge (Penang, Malaysia)

Man-Chung Tang Born in Guangdong, China in 1938. Tang received his engineering degree at Chu Hai College in Hong Kong.

After this, he went to TU Darmstadt, Germany, to receive his doctoral degree in 1965. From 1989 to 1995, Tang was Adjunct Professor at Columbia University in New York City.

Tang also served as chairman of the Cable-Suspended Bridges committee of the American Society of Civil Engineers (ASCE). In his career, Tang designed many bridges in Asia, Europe, and the USA. Most famous examples are the San Francisco-Oakland Bay Bridge in California and the 13.5-kilometer long Penang Bridge in Malaysia.

iants of Asia Mao Yisheng Born in Zhenjiang, China in 1896. Yisheng was a structural engineer, specialized in bridge engineering. He went to Jiaotong University and earned his Master’s degree at Cornell University in New York in 1919. Yisheng was regarded as the founder of modern bridge engineering.

During his career, he designed two of the most famous modern bridges in China, the Qiangtang River bridge and the Wuhan Yangtze River Bridge. Besides bridge engineering, he also led the structural design of the Great Hall of the People in Beijing. Yisheng passed away in 1989.

Photo: Great Hall of the People (Beijing, China)

Photo: Nanning Bridge (Guangxi, China)

Tung-Yen Lin Born in Fuzhou, China, in 1912. Lin was a structural engineer who was the pioneer of standardizing use of prestressed concrete. At the age of 14, he entered Jiaotong University.

In 1933 he earned his Master’s degree in civil engineering at the University of California (UC Berkeley). After graduation, he went back to China to work with the Chinese Ministry of Railways, where he oversaw the design and construction of over 1,000 bridges. He returned to UC Berkeley to develop the practice of prestressed concrete. When Lin received the National Medal of Science from president Ronald Reagan in 1986, he handed over a plan for a 80-kilometer long bridge linking Alaska and Siberia across the Bering Strait named ‘The Intercontinental Peace Bridge‘. In 1954, Lin founded the company T.Y. Lin International, a multidisciplinary infrastructure services firm. Lin passed away in 2003.

“Omdat het oog heeft voor de ontwikkelingen in de maatschappij en de markt èn voor zijn medewerkers.” Margot van de Moosdijk, adviseur

Advies- en ingenieursbureau Movares, actief op het gebied van infrastructuur, mobiliteit, ruimtelijke inrichting, water en energie stimuleert mensen zichzelf te zijn. Wij geven je de ruimte om je leven in te richten op een manier die bij je past en die je capaciteiten tot zijn recht laat komen. Bij ons werk je aan duurzame oplossingen voor maatschappelijk relevante projecten. Met een grote mate van eigen verantwoordelijkheid en volop ruimte voor flexibiliteit en persoonlijke ontwikkeling. En de mogelijkheid om mede-eigenaar te worden. Spreekt dit je aan? Praat eens met ons.

werkenbijmovares.nl Movares Nederland B.V. Utrecht (hoofdkantoor) 030 265 5555 | Recruitment office, 030 265 3880 | movares.nl

China’s latest infrastructural challenge

China’s Hong Kong Zhuhai Macao Bridge By: ir. J.C.W.M. (Hans) de Wit Tunnel Engineering Consultants (TEC) and Royal HaskoningDHV Currently, one of the worlds’ most challenging infrastructure projects, the Hongkong Zhuhai Macao Bridge Link (HZMB) is under construction. The main project covers the offshore section of the HZMB Link of approximately 30 kilometers, crossing the Pearl River Estuary from the border with Hong Kong to Macao and Zhuhai (Mainland China). The Link comprises various bridges, artificial islands, and tunnels. The Link will accommodate a dual carriageway with three traffic lanes in each direction. To allow the passage of sea going vessels, major cable stayed bridges will be included in the design of the Link. The crossing of the main shipping channels at the eastern side of the Pearl River Estuary are realized using a 6.75 kilometers long tunnel, of which approximately 6 kilometers will be immersed. The transition from the bridges to the tunnel has been constructed with artificial islands with a length of 625 meters each.

Challenges in the design Especially the tunnel part is extending the possibilities of immersed tunnelling for the near future. The tunnel will be placed at a very deep level, and consequently has to accommodate large water and ground load. The varying soft soil conditions and adverse marine environment, the offshore conditions for transport and immersion, and last but not least, the 120-years design life in adverse marine conditions meant that a number of design challenges had to be properly addressed.

This is also the case for the artificial islands that form the transition between the bridges and the tunnel. The islands are constructed in very soft soil conditions and require special construction techniques that were developed

by the contractor. A special point of attention was the blockage effect or flow restriction due to the realization of the islands, which was limited to five percent. The shaping of the islands appeared to be important in that respect.

Tunnel Engineering Consultant (TEC) provides the HZMB Administrative Authority with international specialist support regarding the design, construction, and operation and maintenance of the tunnel (in-situ and immersed) and the artificial islands.

KOersief 101 | January 2017 | Structures of Asia

27

Figure1: Indicative geotechnical profile

Tunnel Design The tunnel structure design was faced with a set of challenging design requirements and boundary conditions: 1. The three-lane road design required large spans for the traffic tubes of 14.55 meters.

2. The tunnel is placed at a deep level of 29 meters below the lowest design sea level, to allow the future passage of 300,000 tons oil tankers in two navigation channels with a total width of 2,810 meters. Since the navigation channels will only be dredged in the future, the immersion trench is allowed to fill with sedimentation up to the existing seabed level, which means a ground cover that can exceed 20 meters.

3. The geotechnical conditions are relatively poor and variable. The seabed level in this area varies between -8 and -15 meters. Holocene soft deposits of a thickness of 10-25 meters are found below the seabed and overlying Late Pleistocene (overconsolidated clays, sands, and gravel) with a thickness that varies between 37 meters and 102 meters (locally). Underneath the Pleistocene deposits, rock and granite is encountered.

meters. At the segment joints, special rubber gaskets are applied to guarantee water tightness. The segmental tunnel layout is generally more economic than a monolithic layout (tunnel element consisting of one piece) and more capable of accommodating the adverse geotechnical and surcharge conditions and impact of the accidental load cases.

Foundation Design The structure-soil interaction is one of the governing factors in immersed tunnel design. This includes the foundation bed that is installed between the tunnel structure and the dredged trench and the geotechnical characteristics of the underlying soils.

The foundation bed is required because dredging accuracies generally do not meet the structural limitations related to uneven tunnel support and differential settlements. For the HZMB immersed tunnel, the gravel bed was selected as the most appropriate foundation bed and capable of absorbing moderate to heavy seismic events. A gravel bed can be installed in berms and with a high accuracy from a floating barge in advance of the tunnel element immersion (Figure 3).

The fact that the tunnel element must be able to float during transport and immersion stages implies that there are limitations to the structural dimensions, since the dimensions determine most of the weight of the (floating) tunnel. For the cross section design, it appeared that the conventional reinforced concrete option was on the edge of technical feasibility, resulting in a very high content of rebar.

For that reason, a comparison was made with an option with post tensioning in transverse direction (in roof and base slab). Finally, it was concluded that the conventional reinforced option, with inclined center walls (to reduce the roof span), was still preferred when considering costs, risks, and the execution of the works. The typical cross section is shown in Figure 2.

Figure 3: Gravel bed installation

Based on various studies, it was concluded that the tunnel structure was preferably designed as a segmented tunnel in longitudinal direction. This means that the tunnel consists of individual segments of approximately 22 meters. One tunnel element consists of 8 segments, resulting in a length of 180

Figure 2: Typical cross section Immersed Tunnel (outer dimensions approximately 11.5 by 38.0 meter)

28

KOersief 101 | January 2017 | Structures of Asia

Indicative analyses, which included soil structure interaction, had shown that direct foundation of the tunnel element in the soft layers was only possible when ground treatment was introduced. In this way, the settlements and differential settlements can be limited, and therefore the internal design forces in the tunnel. In addition, ground treatment is applied to promote smooth transition from one tunnel part (e.g. piled cut and cover tunnel at the islands) to the other (e.g. immersed tunnel). Replacement of soft layers by gravel is applied where the soft layers are thin and shallow. On other locations, where the thickness of the soft layer was large, sand compaction piles are applied. The replacement ratio varies from 40 to 70 percent (Figure 4).

Figure 4: Tunnel cross section with sand compaction piles as ground treatment

Cast and launch construction facility For the construction of the tunnel elements, an industrial production method was adopted. This method utilizes the cast and launch construction method, using full section casting, resulting in high quality concrete works. This method was first used for the Ă˜resund tunnel between Denmark and Sweden and was successful in terms of production time and concrete quality.

Concrete immersed tunnels are traditionally constructed by preparing a large (often temporary) excavation, in which the tunnel elements are constructed (Figure 5). The excavation has to be below the water level, so that it can be flooded once the tunnel elements are complete, to allow them to be floated out to their final location.

Figure 5: Traditional construction method

For a tunnel like the HZMB, this method would have involved a huge excavation and extensive water level lowering for a period of years. A basin large enough for all elements would be too expensive; the reuse of a smaller facility for several separate batches was possible, but appeared disadvantageous for the progress and the continuity of the project. The cast and launch method as developed for the Ă˜resund tunnel, allowed for an efficient production, casting 22 meters long tunnel segments in a single 30 to 36 hour concrete pour, full offline prefabrication of the reinforcement cages, and transportation of completed tunnel elements of about 300 meters, sliding over skidding beams into the basin. Then a sliding gate is closed between the factory and the element. Water is impounded within the

Figure 6: Illustration of the tunnel element production facility

Figure 7: Aerial view of the tunnel element production facility

dock to about 10 meters above sea level, allowing the tunnel element to float. It is then winched into deep water of the basin and lowered into the sea, using the same principle as a ship lock. Whilst the completed element is being immersed in this way, the factory is able to continue with the construction of further tunnel elements (Figure 6).

Together with factory facility development, the casting of a full section was studied in order to limit early age stresses, particularly those associated with thermal effects. Traditional construction of tunnel elements, in which the tunnel cross section is casted in three stages, involves this early age stress issue. Since the first cast base slab constrains the later cast concrete of the wall, resulting in tension stresses in the walls that can cause through section cracking, resulting in leakage. These are normally mitigated by cooling the concrete during the hardening process, using cast in water pipes. The chosen construction method largely avoids this problem by casting every tunnel segment in a single pour (3,400 cubic meters in about 30 to 36 hours), so artificial cooling is not required. However, careful consideration was still needed for early age stress management. This included concrete mixture selection, pour sequence, ambient temperature control in the factory, selective insulation of the concrete, and timing of all aspects of the production of a segment (pour, strip, and jack sequence).

Offshore conditions Since the project site is located offshore, the transportation and immersion phase of the tunnel elements have to accommodate offshore conditions. The immersed part consists of 33 tunnel elements, most of them having a length of 180 meters. With the cross sectional dimensions of 11.50 by 37.95 meters, the elements will become the largest concrete tunnel elements in the world. The offshore transport and immersions stages are essential for the tunnel element design and challenging from a risk point of view.

Figure 8: Tunnel element during transportation

KOersief 101 | January 2017 | Structures of Asia

29

This, amongst others, includes the selection of the tunnel element production location, the design wave, wind climate conditions, and many others.

The construction facility for the tunnel elements is located at about 10 kilometers of the project site and during the transport and immersion stages, adverse wave conditions may be encountered. For the transport and immersion design of the immersed tunnel elements, the design forces during the various stages (bending and torsional moments, shear and normal forces) have to be determined and the stability of the floating body has to be considered, where dynamic influences obviously are involved (Figure 8).

Figure 11: Construction of artificial island steel cylinders

Developing an optimal transport and immersion design means that a balance needs to be obtained between structural capacity (quality), acceptable risks, and costs.

Therefore, a design philosophy will be applied, in which a decision model is used based on a wave forecast system, in which numerous wave data are collected. With these data and the weather forecast, a go/no-go decision can be made for every transport and immersion operation, thus limiting risks and enabling design optimizations.

Artificial island design In the HZMB Link, the transition between the bridges and the immersed tunnel will be realized by means of artificial islands. The islands are approximately 625 meters long and 160 meters wide. At the islands, the technical service buildings for the tunnel are located. In Figure 9 and Figure 10, the general lay-out of the islands is shown.

As for the tunnel, the geotechnical conditions for the construction of the artificial islands are not very favorable.

Since large land reclamations and extensive back fill

Figure 12: Preparation building pit for cut and cover tunnel

operations are involved, the geotechnical design is quite delicate in order to meet the settlement requirements that were defined.

The design of the islands includes: • Excavation of the soft top layers of mud; • Sand compaction piles to improve underlying cohesive layers; • Installation of circular steel cylinders as retaining structures; • Infill with coarse sand to be compacted; • Construction of cut and cover tunnel, founded on bored piles; • Formation of the sea defence walls, consisting of rock layers and revetments of doloses; • Finishing works.

Figure 9: Artificial island

Figure 13: Eastern island and cut and cover tunnel under construction

Figures: Header,1-5 Figure 10: Tunnel entrance (at the artificial island)

30

KOersief 101 | January 2017 | Structures of Asia

6-13

Tunnel Engineering Consultants & Royal HaskoningDHV HZMB Authority

Passion for a brighter world Royal HaskoningDHV is een onafhankelijk internationaal adviserend ingenieurs- en projectmanagementbureau met meer dan 130 jaar ervaring. Ons hoofdkantoor is gevestigd in Nederland, met belangrijke kantoren in het Verenigd Koninkrijk, Zuid-Afrika, India en Zuidoost Azië.

Wij voeren wereldwijd, vanuit 100 kantoren in 35 landen, projecten uit die de leefomgeving raken. Onze 7000 professionals voelen zich hierbij gesteund door de kennis en ervaring van hun collega’s. Door de combinatie van wereldwijd opgedane kennis en kennis van de lokale situatie leveren we toegevoegde waarde voor onze klanten in hun projecten.

Wij zien een belangrijke rol voor onszelf in innovatie en duurzame ontwikkeling. Daarom willen we bijdragen aan oplossingen om onze maatschappij duurzamer te maken, samen met onze klanten en anderen die eenzelfde visie hebben.

Stage lopen of een afstudeeronderzoek doen bij Royal HaskoningDHV is een goed begin van een succesvolle carrière.

Vaak ben je lid van een projectteam en werk je mee aan onderdelen van een project. Nieuwe inzichten en kennis zijn zeer welkom bij het zoeken naar de meest ideale oplossing voor een klantvraag.

Op onze website staat meer informatie over wie we zijn, waar we ons in de praktijk mee bezig houden en ons actuele aanbod afstudeeronderzoeken, stages en vacatures.

“Duurzaam bouwen draagt bij aan een positieve invloed van gebouwen op mens en milieu, nu en in de toekomst.

Dat vergt een innovatieve aanpak met het oog op de hele levenscyclus van een gebouw.”

Michiel Visscher, Constructief Ontwerper

royalhaskoningdhv.com

Asia’s first integrated sports, leisure, entertainment, and lifestyle destination

Singapore Sports Hub By: Eline Dolkemade Editor KOersief In 2001, the Singapore Government recommended redevelopment of the existing National Stadium at Kallang Bay into a multi-use sports hub. A design competition was organized, after a commercial model was developed to ensure all facilities would be fully utilized for the first 25 years. Dragages Singapore Pte Ltd, part of the French company Bouygues Constructions, teamed up with Arup and DP Architects and became the winner in January 2008. When the project went more into the detailed design phase, AECOM joined the team. At this phase, 70 architects and engineers were working on the project. By project-end, more than 600 Arup employees had been involved, with approximately 80 employees relocating to Singapore to assist in the delivery phase.

The masterplan Arup’s urban design team recognized the potential of the old Kallang sports stadium, on its prime waterside site, to make the Sports Hub a feature of Singapore’s famous skyline. The team was inspired by the local stories like Kallang Roar, which says that the sound of the 50,000 people in the old stadium could be heard across Kallang Basin, in the city itself. These stories, the silhouette of the city, and the connection between stadium and city contributed to shaping both the masterplan and the form and orientation of the National Stadium. The latter became a horseshoe-shaped bowl, within an openended roof form, rotated to focus on the heart of the city (Figure 1 and Figure 2).

In addition to urban design work, the team had to take into account the poor soil conditions. To avoid constructing large basement areas, the stadium concourse was elevated. This also was a breakthrough in the masterplan, because the elevated stadium created a natural two-story plinth, in which all other facilities could be integrated.

The tropical climate required a unique architectural response because visitors needed protection from sun and rain, both inside and outside the stadium. Structurally, a dome was the

32

KOersief 101 | January 2017 | Structures of Asia

Figure 1: The impressive city skyline visible from the open end of the stadium

most efficient form to achieve the extended spans required to cover this area. The brief also asked for a retractable roof to shade spectators during events, and early calculations indicated that less steel would be required to support the moving roof using a dome rather than a cantilever roof structure.

Figure 2: The waterfront, tree canopy, and shaded walkways are key elements of the plan

Tribune The stadium is the only stadium in the world, custom designed to host soccer, rugby, cricket, and athletics.

This made the challenge for Arup to design a 55,000-seat stadium bowl with optimal view for all of these sports, while minimizing the footprint of the roof dome. Figure 3 shows insight into the size of this project. The brief also required that the lower tier had to be retractable and that all spectators in all tiers benefit from an energy-efficient cooling system. To achieve a balance for both athletics and soccer viewing, the Arup sports venue design team developed a section profile which located almost 30,000 seats within the retractable lower tier. The sightlines were developed to allow these seats to move 12.7 meters closer to the soccer pitch.

Using parametric generation software, the team arrived at a 3D form for the bowl and simultaneously studied the impact of reducing the geometry to the stadium roof. The final design for the bowl enabled the long span at the dome to be reduced to 310 meters. However, at this diameter, it was still the largest free-spanning dome structure in the world.

Structural design A specialist team within Arup was tasked with developing bespoke software to manage inputs from various design software used in the design process. The latest BIM modeling software was essential to the integrated architectural design and engineering, particularly for the stadium roof. The design team wanted a feedback loop so that one software could inform another of defined positions, coordinates, and dimensions for the roof elements. A parametric model was built in Digital Projects (DP), allowing the roof structure to

be quickly assessed structurally and redefined as the design developed.

Roof design The dome roof form was chosen as it is inherently a highly structurally efficient geometry for a roof structure of this scale, especially one that integrates a retractable roof. Singapore is a unique location – no significant seismic activity, low wind and, of course, no snow load – so it provided the Arup team with a unique architectural and structural opportunity. The initial target was to reduce steel weight by leveraging the inherent efficiencies of the shell roof form. One outcome was a gradual reduction in depth of the primary structure towards the ground, from a maximum depth of 5 meters to the center of the dome to 2.5 meters at the base. Two control surfaces were established to define this, a sphere at the top and a torus at the bottom surface. This optimized structural solution provided an architectural benefit at ground level by reducing the proportions of the structure to something more in touch with the human scale.

Reducing dead load wherever possible was a key goal and the team estimated that for every 10 kilograms of weight added to any part of the shell structure, a further 4 kilograms would need to be added to hold it up. This was a strong influence in the design of the moving roof structure, as well as the moving and fixed roof cladding design. The result is a dome that uses one third of the steel weight per square meter, compared to other large-span structures of this scale.

Figure 3: Sydney Opera House would sit comfortably inside the stadium

The team wanted to simplify the detailing of all complex node intersections across the entire roof and developed a standardized family of node details that could be replicated wherever possible. This required an update to the geometry of the roof to achieve a more symmetric design than the competition-winning roof geometry. An additional parallel truss was added, the main gutter trusses were realigned, the geometry of the roof opening was adjusted, and the diagonal trusses were simplified.

The 9-meter tall plinth serves as a post-tensioned concrete ring beam, which acts to restrain the roof from spreading.

The roof has a 310 meters span and rises to a height of approximately 85 meters from ground level. The fixed roof spans freely across the stadium without support from the concrete stadium seating bowl structure. The movable roof is supported, via a series of supports running on the parallel runway trusses that span perpendicular to the pitch axis,

KOersief 101 | January 2017 | Structures of Asia

33

by the fixed roof. All loads on the roof are transferred to the concrete ring beam by a network of triangular-formed primary trusses, which create a very stiff 3D dome structure.

The fixed roof and two movable roof components consist of approximately 7,400 tons of structural steel plus connections.

There is an opening in the roof, approximately 220 meters long and 82 meters wide, over the football pitch. The shell action of the fixed roof is affected by the opening in the roof, where point loads from the supports on the runway trusses result in additional bending in those trusses. Across the opening, the primary trusses act in bending and compression to support the movable roof as the roof closes. The ring beam and ring beam support column pairs restrain the thrust forces generated as the steel roof tries to spread, and transfer vertical forces at each of the roof nodes to the columns below.

These vertical forces are then transferred by the columns into the bored pile foundation.

A number of different connection types were investigated for the complex geometry of the tube-to-tube connections of the fixed roof. Three key factors were assessed when selecting the connection detail: fatigue sensitivity (use of stiffener plates, slotted plates, and cruciform within connections can greatly reduce the fatigue life of connections), ease of fabrication, and ease of design. A connection, formed from one continuous member and profile cutting and welding all other members to it (Figure 4) was selected as the preferred fabrication option and the least fatigue sensitive detail, although more challenging to design. The continuous member is referred to as a ‘thickened can’.

to illuminate the moving roof at night (Figure 5). Sized at 20,000 square meters, the moving roof is one of the largest addressable LED screens in the world and an unmistakable feature on Singapore’s skyline.

The flexibility of the moving roof structure required a design with sliding bearings. Therefore, it became important to avoid small pillow modules because intersections between extrusions would require fixed joints (something that would not work structurally). Also, as an actively inflated roofing system, it carried the risk of pillows deflating (either through puncturing or pump failure) so water ponding was a serious design concern. It was decided to change the pillow format to long extruded pillows that ran parallel to the short edge of the moving roof. In this way, water would not be retained in the moving roof area, and junctions between extrusions could be minimized.

Figure 5: The roof is made of multi-layer ETFE pillows and embedded with LEDs, turning it into a large digital screen

During the competition phase of the project, Arup developed designs for the moving roof mechanism based on a range of drive options. The geometry of the dome roof and the desire to reduce steel weight led to selection of a cable driven mechanism. A significant benefit being of this mechanism was that it allowed for less stringent control on the deflection criteria between the fixed and moving roofs. This in turn allowed for efficiencies in roof steel weight.

Figure 4: Finite Element Analysis model of a fixed roof connection node

Moving roof cladding Similar to the fixed roof, the movable roof is constructed out of 3D triangular trusses, which span approximately 48 meters between the runway trusses. There are four spans of movable roof trusses between the five supporting runway trusses.

A lightweight cladding system was required for the moving roof to provide shade to the seating bowl and reduced solar heat gain, while at the same time offering translucency so that the event space could be naturally lit during the day.

A multi-layer ETFE pillow was chosen to meet these design requirements and at the same time provide the opportunity

34

KOersief 101 | January 2017 | Structures of Asia

Conclusion Innovative ideas were nurtured and unique concepts were developed and delivered to make the Sports Hub a venue that perfectly matched its location. It meets all of its objectives: providing sporting facilities for the city’s residents, a spectacular setting for international sporting fixtures and world-class concerts, and – perhaps the most important of all – a home for the National Day Parade when the people of Singapore come together to celebrate their city’s independence. As a magnificent sporting and event facility, the Sports Hub will serve Singapore well for many decades to come.

References: [1] Singapore Sports Hub, The Arup Journal, Issue 1, 2005, Andrew Henry, Chia Wah Kam, Clive Lewis, Malcolm Smith, Mike King, Nick Boulter, Peter Hoad, Ruth Wong, Scott Munro, and See Lin Ming Figures: Header 1,3,4,5 2

Darren Soh Arup SHPL/Oaker

Powerful Software for Structural Engineering Fabrication and Construction

Wil jij als student je marktwaarde verhogen, je grenzen verleggen en werken met een software-tool die gebruikt wordt door vele toonaangevende ingenieursbureaus in Nederland?

?

Wil jij werken met software die met 8000 licenties bij meer dan 5000 engineers wereldwijd ruim is vertegenwoordigd?

Download onze studentenversie www.nemetschek-scia.com/nl/studenten Nemetschek Scia B.V., Wassenaarweg 40, 6843 NW Arnhem, Nederland, Tel.: +31 26 320 12 30, info@scia.nl, www.nemetschek-scia.com

AdvKOers-2014.indd 2

12/4/2014 4:37

Gratis software voor studenten & docenten TU Eindhoven!  GRATIS gebruik van alle BuildSoft software voor alle TU/e studenten & docenten  Raamwerken & platen, 3D gebouwen, staal, beton & hout, verbindingen, seismisch, ...  Volledige versies - geen beperkingen!  Eenvoudig & snel te gebruiken!

Jouw GRATIS licentie in 5 stappen: 1. Registreer je als student op http://www.buildsoft.eu/nl/students Je ontvangt meteen de bevestigingsemail met login en paswoord.

2. Log in op de website, sectie ‘Downloads’.

3. Installeer de software naar keuze.

4. Vraag online je gratis licentie aan. Instructies vind je in de bevestigingsemail.

5. Je ontvangt na enkele werkdagen jouw gratis licentie per email.

Meer info of vragen: studenten@buildsoft.eu

KOersief 101 | January 2017 | Structures of Asia

35

Adviesbureau Van de Laar is een onafhankelijke en betrouwbare partner bij het verwezenlijken van de

.

droom van elke opdrachtgever.

We zien het als een uitdaging om constructief mee te denken in het technisch realiseerbaar maken van bouwprojecten.

Rozet, Arnhem Foto: scagliolabrakkee/ © Neutelings Riedijk Architects

Constructief vernuftig, optimaal geïntegreerd en duurzaam

Advies- en Ingenieursbureau Van de Laar bv Brucknerplein 19 5653 ER Eindhoven

Bastionder, Den Bosch Van Roosmalen Van Gessel

Telefoon: (040) 25 26 625 Internet: www.vandelaar.info E-mail: info@vandelaar.info

Let’s connect?!

Wil jij zien op welke wijze Heijmans aan de ruimtelijke contouren van morgen bouwt? En ben jij nieuwsgierig welke spraakmakende en innovatieve concepten Heijmans ontwikkelt en realiseert?

HeijmansNL Facebook “f ” Logo

Blijf dan up-to-date en volg ons op Facebook & Twitter!

CMYK / .ai

Facebook “f ” Logo

CMYK / .ai

HeijmansNL

Master’s thesis

FDS-2-Abaqus: An automated CFD fire to FE thermo-mechanical coupling program By: J.A. (Jelmer) Feenstra MSc Supervisors: dr.ir. H. (Herm) Hofmeyer, prof. M. (Mahem) Mahendran, ir. R.A.P. (Ruud) van Herpen The danger of fire to both human safety and structural integrity is generally understood. The traditional approach of investigating structural response to fire is by imposing prescriptive time-temperature curves on the structure. However, the use of these simplified time-temperature curves does not take into account the randomness of fire, and therefore cannot accurately represent the fire. More advanced numerical models based on Computational Fluid Dynamics (CFD) are capable of modeling the three dimensional fire propagation more accurately. In addition, advanced numerical models based on the Finite Element Method (FEM) are used nowadays to predict local and global structural behavior.

These methods have been applied to predict structural response to fire. Therefore, a more realistic fire and failure behavior can be obtained by coupling a CFD fire simulation to Finite Element (FE) thermal and structural analysis, often referred to as a coupled fire to thermo-mechanical analysis (Figure 1).

The aim of this thesis was to study the feasibility of the two-way coupling of CFD fire simulations to FE heat transfer and structural response analyses, as illustrated in Figure 1.

Several programs and scripts were developed to facilitate and automate both one- and two-way CFD-FEM coupling.

The developed managing program FDS-2-Abaqus was used to perform one- and two-way coupled analyses on an office space, comprising a twelve plate thin-walled steel facade.

The results were used to assess the effectiveness of two-way coupling.

Figure 1: Two-way coupling of CFD fire simulation to finite element thermal and structural analysis

Coupling of CFD fire simulations to thermal and structural Finite Element Analyses (FEA) is a relatively new area of research. One of the reasons for the resurgence of interest in thermo-mechanical response to fire was due to the attacks on the World Trade Centre (WTC) towers in 2001. In the aftermath of the collapse, Prasad and Baum, who were working on the collapse analysis of the WTC, developed an interface model that coupled CFD with FEA based on heat transfer by radiation and conduction.

Several other studies can be found in literature [2]. What they have in common is that these coupling methodologies focus on fire to thermal and thermal to structural coupling interactions, both one- and two-way. However, the effect of structural response on the fire propagation and further failure progressions is neglected. For instance, failure of a window or a local element results in an opening which changes the fire behavior, and consequently influences the fire load on the structural elements. In other words, the two-way coupling between the fire and structural model is typically neglected and needs to be studied.

Methodology A coupled fire to thermomechanical analysis can be split into three separate types of analyses: (A1) fire simulations, (A2) thermal response analysis, and (A3) structural response analysis. These analysis steps are mutually coupled by three coupling steps: (C1) Coupling of the fire simulations to heat transfer analysis, (C2) coupling heat transfer to structural analysis, and (C3) coupling of the structural response to the (original) fire simulation, in which the latter is exclusive to the two-way coupling procedure. In other words, a distinction is made between a one- and two-way coupling procedure, where for a two-way coupling, the influence of structural changes on the fire propagation are taken into account. This sounds as a relatively small difference, but it actually has a large influence on its implementation. The reason being that the one-way coupling approach is a linear process, while the two-way coupling is an iterative process.

Figure 2: Methodology for the one- and two-way coupled fire to thermomechanical analysis. Subdivided in three analyses (A#) and three coupling (C#) steps. Where the coupling of the structural response analysis back to the fire simulation (C3) is exclusive to the two-way coupling

KOersief 101 | January 2017 | Structures of Asia

37

The one-way coupled analysis consists of a fire simulation for the full duration of the intended analysis and then continues sequentially with the heat transfer and structural response analysis, again for the full duration. In the two-way coupled analysis, one needs to verify, during the fire simulation, if (some part of) the structural model has failed and if so, this needs to be removed from the fire model. Basically, a fire is simulated for a small time increment and then it is checked, using a coupled heat transfer and structural response analysis, whether structural integrity is still met. If failure occurs, the fire and structural models are updated for the next iteration.

Ideally, the time increment size approaches single calculations steps. In other words, the approach to two-way coupling is a combination of a limited number of one-way coupled fire to thermo-mechanical simulations. After each one-way coupled increment the geometric changes are updated in the fire, thermal, and structural models.

as represented by the flowchart in Figure 3. Starting with upGeomFDS, where additional code is written to the FDS input file to interrupt the simulation at the user-defined time (iteration) interval. After updating, the input file is used in the first analysis step, the fire simulation. The thermal output generated by the fire simulation is then rewritten by the reWriteAST2Py program into a python script that can be read directly into Abaqus. Similar to updating the FDS input file, additional code is written to the Abaqus heat transfer (HT) script, by the upGeomHT subprogram, to include the thermal data and interrupt the simulation at the user-defined time interval. Subsequently, the Abaqus heat transfer analysis is run, thereby obtaining the temperature distribution in the structural system. This output can be put directly in the structural response analysis (SR) so no additional post-processing is required. As with the previous upGeom subprograms, the script for the SR analysis is updated with the temperature distribution and time interval for the current iteration in the upGeomSR subprogram.

Afterwards, the Abaqus structural response analysis is run, obtaining the deformation and stress distribution of the structural system. In the last step, the stress distribution of the structural plates is checked versus the user-defined failure criteria and possible failure is recorded in a log file.

This log file keeps track of the failure progression and is used in the upGeom programs in subsequent iterations to remove failed plates from the fire simulation and the temperature and structural analyses. After completing the coupling simulation, the program summarizes the results as illustrated in Figure 4.

Figure 3: Flowchart of FDS-2-Abaqus and its subprograms. The white colored processes represent the fire simulation, the heat transfer (HT), and the structural response (SR) analysis respectively. The black colored squares represent the developed subprograms/scripts. The name of the program/script and its typical function are included in the separate processes

FDS-2-Abaqus FDS-2-Abaqus is a command prompt based program developed in C++ to manage the one- and two-way coupling of a CFD Fire Dynamic Simulator (FDS) fire simulation to an FE Abaqus Heat Transfer (HT) and Structural Response (SR) analysis. Various scripts and (sub)programs, using programming languages C++ and python, were developed to facilitate the coupling procedures. The FDS-2Abaqus program structure is summarized in the flowchart in Figure 3. The basic procedure will be discussed below. For a detailed discussion on the developed programs, scripts, simulations, and the (approach to) coupling reference is made to the Master’s thesis [2].

Initially, the program prompts the user for various parameters concerning the model setup, simulation duration, iteration size, and failure criteria. For a one-way coupled approach, the iteration time-size should be equal to the total simulation duration. After this initial setup, the program will iterate through the various functions

38

KOersief 101 | January 2017 | Structures of Asia

Figure 4: FDS-2-Abaqus console summary for a two-way coupled analysis

Coupling Effectiveness FDS-2-Abaqus was used to study the failure progression of a thin walled steel facade, comprising twelve plates using both a one- and two-way coupled approach. Multiple simulations were performed for both the one- and two-way coupled CFD-FEM analysis. The one-way coupled (OWC) simulation consisted of a single iteration with a duration of 1,800-seconds. The two-way coupling (TWC) was subdivided in 150 second iterations, for a total of 12 iterations, where after each iteration, the model geometries were updated (automatically). The results are summarized below.

The results clearly show a significant difference in fire and failure behavior between the one- and two-way coupled simulations. Although the various simulations differ slightly in failure progression, their overall trend is alike, as indicated

Figure 5: Number of failed plates over time for the one-way coupled analysis

Figure 6: Number of failed plates over time for the two-way coupled analysis

Figure 7: Smokeview visualization of the one-way coupled CFD-FEM simulation at 710 seconds

Figure 8: Smokeview visualization of the two-way coupled CFD-FEM simulation at 715 seconds

by the red marker line in Figure 5 and Figure 6. From the smokeview visualizations, in Figure 7 and Figure 8, it is clear that the additional airflow, due to plate failure, refocuses the fire to the middle of the compartment, away from the structural facade. Thereby greatly reducing the thermal load on the structural facade and limiting its failure progression.

It is important to note that the fire behavior, illustrated in Figure 7 and Figure 8, does possibly not accurately represent a real life fire. The symmetric redistribution of the fire to a centralized position, while the openings on either side differ greatly, points to a questionable difference in air velocities.

In addition, no real life fire tests have been conducted to verify the results.

Conclusions Initial studies using the FDS-2-Abaqus program show a significant difference in the failure progression of a

facade wall between a one-way and two-way coupled analysis. This difference was governed by the change in fire propagation due to geometric updates in the fire, heat transfer, and structural response models. However, it is still too early to give an all conclusive answer on the added value of a two-way coupled approach compared to a one-way coupling approach, mainly due to the lack of validation and the simplified approach to reality. Still, it is clear that the influence is of significant magnitude for further analysis.

References: [1] K. Prasad and H. R. Baum, “Coupled fire dynamics and thermal response of complex building structures”, Proc. Combust. Inst., vol.

30, no. 2, pp. 2255–2262, Jan. 2005.

[2] J. A. Feenstra, “FDS-2-Abaqus: C++ Managed Automated Python Scripted CFD-FEM Coupling, Additionally assessing two-way coupling effectiveness”, Eindhoven University of Technology, 2016.

KOersief 101 | January 2017 | Structures of Asia

39

Master’s thesis

Cold bent glass fins in a lattice gridshell By: J.P. (Joey) Janssen Supervisors: prof.dr.-ing. P.M. (Patrick) Teuffel, ir. A.P.H.W. (Arjan) Habraken, ing. L.A. (Luis) Weber Cold bending of glass fins in a lattice gridshell is a new concept. It is a transformation of the well-known timber gridshells into glass and is inspired by the most famous example of the Multihalle designed by Frei Otto. The reason for using glass is because of its transparency, which makes it possible to apply this concept as transparent facade in a building.

However, glass is not timber; it is very fragile and it has a low stiffness in comparison to aluminium. The application of glass as a structural material is not new, and is rising in the application as straight beams and columns in transparent roofs and facades; also called glass fins. In this study, these fins are flipped on their side and bent about their weak axis in order to shape a double curved facade.

Origin of the double-curved glass facade The double curved glass facade is a revisit of the Statoil Headquarters, which is built in 2011 in Oslo, Norway. This office building consists of five stacked blocks of 100 by 25 by 11 meter, enclosing an internal courtyard. With the insulated glass facade in the gaps between the blocks, an interior climate is created. The key requirement ‘transparency’ resulted in the improved concept of cold bent glass fins in the lattice gridshell as a replacement for the steel structure system currently used (Figure 1). Because the goal of the project is to investigate the potential of this concept, a

Figure 1: Statoil Headquarters (2011), Oslo

40

KOersief 101 | January 2017 | Structures of Asia

parametric model is developed in Grasshopper, a plugin for Rhinoceros. The dimensions of the facade are the variables.

A smaller set of dimensions is used for the research that is performed.

Form-finding methodology The reason for using cold bending glass fins is the manufacturability and transportation of the glass elements, which is the easiest when they are flat and straight. The cold bending happens on-site, and for this, a generic formfinding method is developed in the parametric model.

Figure 2: Structural system concept

This method is based on the ‘compass method’ [1] that Frei Otto used for his timber gridshell, but with some additional requirements for the application of glass. A form-finding loop is used, with every loop consisting of two steps: a geometric step, which is used to draw the gridlines, and a mechanic step, which assigns physical properties to those gridlines [2].

curvature in the fin is ensured in the form finding by means of the projection of a straight line on the surface with a projection vector. This vector is determined with the use of a specially developed ‘vector solving method’, which uses the surface normal vectors of the facade. This method pushes the glass fins flat on the surface and also ensures that there is no undesirable twist in the fin (Figure 4).

For the geometric step, a newly developed ‘pipe method’ is used, which controls the distance between the gridlines. A pipe is drawn around a base line, and the intersection of this pipe with the facade surface defines a new line. In every step that follows, the previously defined gridline is used as the centerline for drawing the new pipe, which again defines a new gridline. By means of this iterative process, the facade can be covered with gridlines (Figure 3).

Both the geometric and mechanic step are used in every loop of the form finding method. The pipe method approximates the location of the new line and the vector solving method. The projection of the lines ensures a single curvature and no twist in the glass fin, resulting in the base for every next loop.

The mechanic step assigns the specific physical properties for using glass fins. In comparison to the timber gridshells, glass fins cannot bend and twist in all directions. The timber laths have a square cross section, while the glass fins have a cross section with a width to thickness ratio of approximately 20:1. This results in a stiffness ratio of 400:1, which makes the glass easy to bend in one direction, but almost impossible in the other direction. The single

Figure 4: Vector solving method

Figure 3: Pipe method

Assessment of glass fins On account of safety reasons, laminated glass fins are applied in the gridshell. If one layer should break, the other layer(s) will hold the fin together and prevent the dangerous situation of falling glass. The assessment of glass in general, and laminated glass in particular, has a time dependent value. In the analysis of a laminated glass element, the relaxation of the interlayer influences the bending resistance of the cross section. With an effective thickness, the thickness of the laminate composition can be described as a single layer with a smaller thickness. This means that there could be a different effective thickness for different load durations.

KOersief 101 | January 2017 | Structures of Asia

41

The strength of glass is determined with an equation, containing multiple factors, of which the modification factor depends on the load duration. The building standards (NEN 2608:2014 [3]) state that the shortest load duration reference time may be used. This can result in a stress limit of about 80 N/mm2 when there is a wind load of 5 seconds, but a limit of 60 N/mm2 when there only is a permanent load of the cold bending. This would mean that an additional wind load on the facade has a beneficial effect on the strength value which is incorrect. Therefore, a unity check is defined where cold bending and the external load have their own strength value, and the two unity checks are summed up:

∑

σ pl ; mt ; d ; t fmt ; u ; d ; t

≤ 1.0

Optimization methodology An optimization has no meaning until the optimization goal is defined. For the facade, a reduction of weight is chosen. It reduces the amount of material necessary and the amount of load that the surrounding structure has to carry. The optimization is driven by the reduction of the thickness of the glass fins (which has the largest influence on the cold bending stresses), load bearing capacity, and in some cases, a buckling phenomenon.

To find the optimal solution for the thickness, a bisection optimization method is scripted in Grasshopper. Every step in the optimization contains a structural analysis performed with Abaqus, controlled from Grasshopper. This process starts at the upper limit for the thickness that is defined by the cold bending curvature necessary for shaping the facade. By stepwise bisecting the thickness range (meaning: divide in two equal parts [4]), the optimization converges to the optimal thickness with an accuracy of 1 millimeter. With the use of the effective thickness of a laminate composition, the best applicable laminate composition is searched in close range of the resulting thickness from the bisection optimization.

Results The research performed with the parametric model investigates the potential of the lattice gridshell composed of glass fins. The optimization of the structure reduces the thickness and could cause second order buckling during the geometric non-linear analysis. Because of the high level redundancy of the gridshell, redistribution of forces allows for manageable buckling and failure wil not directly occur.

Ultimate failure can occur because of two reasons (Figure 5): first, the buckling effect causes a large curvature with

Figure 5: Principal stresses, glass fin thickness of 10 millimeters (left) and 5 millimeters (right). Deformation scale factor = 20.0

42

KOersief 101 | January 2017 | Structures of Asia

corresponding peak bending tensile stresses (left); second, a peak tensile stress in the glass fins that are in tension. The optimum is defined as the smallest thickness of the glass fins that meets the strength criteria described in the summation of unity checks.

Proof of concept The proof of concept of the cold bending of glass fins is conducted by means of the manufacturing of a mockup. The mock-up consists of a steel frame of 1.5 meters by 1.5 meters with two glass fins of 2.3 meters spanning diagonally in the frame (Figure 6). A mechanism at the intersection tightens the glass fins together, introducing the cold bending. The spacing between the glass fins in the undeformed state is 200 millimeters and the limit (with material safety factors) for the cold bending deflection is 115 millimeters per fin. A safe proof of concept was ensured when each fin deformed 100 millimeters to one another.

Figure 6: Mock-up produced at Octatube, total deflection of 115 millimeters

Concluding The twist in the facade is limited by the cold bending of the glass fins. The thickness to use for the glass fins is influenced by the cold bending stress and by the necessary load bearing capacity of the gridshell. First, a reduction of cold bending stress can be achieved by reducing the thickness and second, the load bearing capacity can be enhanced by increasing the thickness. Solving this contradictory requirement of the thickness defines the optimal solution and the possible twist within this concept.

Recommendations for further research are validating the summation unity checks in the assessment of glass fins and the admissibility of the manageable buckling.

References: [1] Tayeb, F., et al., 2015. Design and realisation of composite gridshell structures. Journal of the International Association for Shell and Spatial Structures: J. IASS. p.49-59. Paris: UR Navier, Université Paris-Est, Ecole des Ponts ParisTech [2] Otto, F., Hennicke, J. and Matsushita, K., 1974. IL 10: Gitterschalen.

Stuttgart: Institut für Leichte Flaächentragwerke [3] Normcommissie 353005 “Vlakglas”, 2014. NEN 2608, Glass in buildings – Requirements and determination methods. Delft: Nederlands Normalisatie-instituut [4] Burden, R.L. and Douglas Faires, J., 2005. Numerical Analysis, eight edition. Belmont: Thomson Brooks/Cole Figures: Header, 3-6 1 2

Joey Janssen www.rnz.de / www.octatube.nl / Joey Janssen https://www.dezeen.com/

KOersief 100 contests By: Sander Montrée Editor-in-chief KOersief 100 In the 100th KOersief we challenged you with three contests. The answers are given below. Further details on the scoring can be found on our website: www.KOerstue.nl/KOersief100.

Tensile strength of KOersief 99 Guessing the tensile strength of a non-structural element can be quite difficult, and calculating it can be even harder.

The best way is therefore testing it. From the test we can say that the 99th edition of the KOersief has a tensile strength of 11.8 kilonewton.

KOers Scrabble® The Secretary wins the game with a final score of 420 against the Chairman’s 417 points. The final board can be seen here.

Gratis software voor studenten & docenten TU Eindhoven!  GRATIS gebruik van alle BuildSoft software voor alle TU/e studenten & docenten  Raamwerken & platen, 3D gebouwen, staal, beton & hout, verbindingen, seismisch, ...  Volledige versies - geen beperkingen!  Eenvoudig & snel te gebruiken!

Jouw GRATIS licentie in 5 stappen: 1. Registreer je als student op http://www.buildsoft.eu/nl/students Je ontvangt meteen de bevestigingsemail met login en paswoord.

2. Log in op de website, sectie ‘Downloads’.

3. Installeer de software naar keuze.

4. Vraag online je gratis licentie aan. Instructies vind je in de bevestigingsemail.

5. Je ontvangt na enkele werkdagen jouw gratis licentie per email.

Meer info of vragen: studenten@buildsoft.eu BuildSoft - structural design analysis software | http://www.buildsoft.eu | info@buildsoft.eu | +32 (0)9 252 66 28

KOers Education Update By: Eline Dolkemade Commissioner Education 47th board KOers The education after the Bachelor inside the TU/e is shaped in the TU/e Graduate School. One of the main points of the Graduate School, which includes the Master program, is that students can put together their own individual curriculum.

Within the Master, you choose a core program, such as Structural Design. The core program consists of the following subjects:

More information about courses and the form for the Personal Study Plan can be found on: https://static.studiegids.tue.nl/ > Master program’s > Master Architecture, Building and Planning

Subjects

1

Core Courses

25 ECTS

2

Specialization Electives

30 ECTS

3

Faculty wide Electives

20 ECTS

4

Graduation Project

45 ECTS Total

120 ECTS

As soon as possible, but preferably at the end of the first quartile, you have to write your ‘Personal Study Plan’ and this needs to be approved by a mentor. The personal study plan contains the courses you will follow and a time schedule.

For the unit Structural Design, your mentor is ir. B.W.E.M. van Hove. When you have discussed your study plan with her, you can submit it at floor 2.

Van Rossum Raadgevende Ingenieurs bv Amsterdam Pedro de Medinalaan 3a 1086 XK Amsterdam Postbus 37290 1030 AG Amsterdam T +31(0)20 615 37 11 amsterdam@vanrossumbv.nl www.vanrossumbv.nl

Van Rossum Raadgevende Ingenieurs bv Rotterdam Westblaak 5e 3012 KC Rotterdam T +31(0)10 404 51 11 rotterdam@vanrossumbv.nl www.vanrossumbv.nl

Graduation Project Before you start your Graduation Project, you must find a subject. Therefore, you can make an appointment with a supervisor to ask what his or her available subjects are or you can propose a subject of your interest. Subjects for Graduation Projects may focus on the design of a building, a research topic, or a combination of these. A research oriented project often has both an experimental and a numerical component. When you have found a subject and a supervisor, you can complete the study plan and submit this again on floor 2. Before starting the Graduation project, you also have to subscribe to course code 7K45M0 on Oase.

Keep in mind that the Graduation Projects is 45 ECTS, thus the amount of work is equivalent to that of three full time quartiles.

Van Rossum Infra bv Pedro de Medinalaan 3a 1086 XK Amsterdam Postbus 37290 1030 AG Amsterdam T +31(0)20 61 73 975 infra@vanrossumbv.nl www.vanrossumbv.nl

Van Rossum Raadgevende Ingenieurs Almere bv Kerkstraat 97 1354 AA Almere Postbus 105 1300 AC Almere T +31(0)36 531 15 04 almere@vanrossumbv.nl www.vanrossumbv.nl

The structural designer of the future – computational design and digital manufacturing

‘In Dialogue With..’

By: Lieneke van der Molen Commissioner Education 46th board KOers ‘In Dialogue With..’ is an activity of Study Association KOers, where students go in a discussion or a dialogue with professionals from the structural design discipline. On October 13th, a dialogue took place with the theme ‘the structural designer of the future – computational design and digital manufacturing’, in which the future of the structural designer due to the current developments in the built environment was discussed. Wessel van Beerendonk (architect and co-founder of StudioRAP), Frank Huijben (structural designer and project manager at ABT Ingenieurs in Building technology), and Arjan Habraken (lecturer TU/e) were invited for this edition of ‘In Dialogue With..’. They went in dialogue with 19 students.

After two inspirational presentations, it became clear that digital manufacturing will be the future; without the computer we cannot do anything. The first theorem of the evening was about education. In addition it could be said, that the students bring new things into education and the lecturer is watching along with them. However, it should be the other way around. The lecturer should be the one to show current developments in the built environment and the student is the one who has to figure out how to apply them. This new wind at the university can result in possible changes, so it is essential that the student is willing to invest his or her time if they want to apply these developments.

This has the positive consequence that each student can offer different knowledge, resulting in a greater variation of structural knowledge.

Figure 1: The students are listening to one of the inspirational presentations

manufacturing is not just a hype. All participants agreed that it is not a hype. It takes time to remove all the bugs from the new developments and this is what we are doing now. The optimization of these developments does not only have an impact on the structural design discipline, but other disciplines should be involved in these developments as well. This requires the ability of not thinking in boxes, but to think in working groups with common professionals. A basic knowledge of multiple disciplines is necessary, but it is important that you specialize in your field of interest.

In practice, money is a greater decisive aspect than durability. Different boundary conditions can change this and leads to different considerations or results. In addition to the project-based elaboration, one can choose to elaborate the project in a different manner parallel to the actual project. This is innovative, and perhaps appropriate for the university and student, because they have the opportunity to go in the extreme, even when it is not realistic.

Whether the new developments will take over the market in the future remains to be seen. It is good to have knowledge to ensure an extra tool in your toolbox. As a new structural designer, you will first need to make some steps to gain experience. When you want to apply something new in a project within a company, it is important that you are doing something you like. You need to convince one another with your knowledge that you have obtained in your own time during your study.

The second theorem of the dialogue included the role of the structural designer, namely that one may become a computer specialist (IT). The ‘computer specialist’ might be a wrong name; perhaps the ‘data specialist’ would be better.

This person will partly take over or support the task of a structural designer, and therefore becomes a new expert in the building team. This results in multiple different structural designers: the creative one with structural insights, one that goes into the IT discipline, and one that will make the link between these two. Communication will be an important aspect.

A hype provides an accelerated study, in which many changes are discussed, resulting in something that works and can be applied. With the third theorem, a discussion was held whether computational design and digital

Figure 2: Setting during the dialogue

KOersief 101 | January 2017 | Structures of Asia

45

Column

‘Bitcoin mining’ university Hans Lamers

Colophon KOersief is a student magazine published three times per year by KOers, section association Structural Design within study association CHEOPS and the unit Structural Design of the department of the Built Environment at the Eindhoven University of Technology.

KOers VISITING ADDRESS Vertigo 2 Groene Loper 6 5612 AZ Eindhoven tel. 040-2474647

Over the last three thousand years, money has made the world go around. This has led to our present worldwide market economy. From precious metal coins and printed figures on ordinary lightweight paper, our cash has evolved into digital e-money. In some cases, it is possible to pay simple goods with the smartphone. A peculiar kind of money is the bitcoin, which can be denoted as a cryptocurrency.

This virtual coin makes use of an open source software where you can transfer ‘value’ to another bitcoin address.

Due to the encryption, a person can spend the coin only once. There is no bank, no interference with the government, and no guided inflation. This seems ideal for criminal transactions and money laundering, but some things in the digital blockchain remain traceable. More interesting is the generation of new bitcoins. New bitcoins are created as a reward in the competition between users, who offer their computing power to verify and record transactions in the blockchain. This process of so-called ‘mining’ is controlled by very complex algorithms. The value of a bitcoin depends on the number of ‘miners’, the mining power, the rewards, and fees. Although many miners became millionaire in the past seven years, the future is rather blurry.

Why these reflections about money? Simple, our university is facing financial problems in the years to come. Our department ‘The Built Environment’ also has to downsize the number of employees. This will negatively affect the quality of education and quantity of research. Not a friendly perspective. If we bundle all our computer power, we maybe can become the best ‘bitcoin mining’ university in the Netherlands and we still may have a chance to survive the financial crisis? That is my contemplation, or is it just a hopeful daydream?

POSTAL ADDRESS Vertigo 9 Postbus 513 5600 MB Eindhoven e-mail: KOers@bwk.tue.nl

47th board of KOers 2016-2017 Chairman Lars Croes Secretary & Com. Education Eline Dolkemade Treasurer Lia de Mooij Com. Public Relations Thomas Dam Editorial board KOersief 101 Editor-in-chief Thomas van Vooren Eline Dolkemade Tom Godthelp Denise Kerindongo Caroline Koks Lieneke van der Molen Angelique van de Schraaf K-M@il and website Every other week, a K-M@il news update is sent by e-mail.

Visit our website and Facebook page regularly for recent news messages and events. On our website, you can subscribe for activities, check photos of past events, and read previous editions of the KOersief.

Proofreading Niels Hanegraaf Arno Poels Cover FLICKERVERTIGO Centerfold made by Richard de Rijk Nanjing Yangtze bridge - Flickr user Jingtian Lv Penang bridge - Flickr user kennysk Great Hall of people - Photo via ZhengZhou/Wikimedia Nanning Bridge - Flickr user Samyuen1 Photo 47th board Robbert de Smet Print run 400 copies, distributed to students, professors, sponsors, and other relations of study association KOers.

Printing office Meesterdrukkers BV, Eindhoven

46

KOersief 101 | January 2017 | Structures of Asia

© Copyright KOers 2017