TECTONICS IN ICONIC BUILDINGS

National Stadium andNational Aquatics Center

Beijing

15.sept - 2008Magnus Aursand

INDEX

A traditional card house 1Approaching the problem 2National Stadium, Beijing 3National Aquatics Center, Beijing 5Two stadiums, two concepts? 8Iconic tectonic or just some new technology? 10Sources 12

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A TRADITIONAL CARD HOUSE

“Architecture begins when two bricks (stones) are put carefully together” Mies van der Rohe

If you build a traditional house of cards, a card house, is it important that every card in the house holds its position. If you remove one of the cards from the lowest level of the card house, everything falls apart. How do all the elements in a building play together in a most efficient way? It’s important that every element depends on each other. This card house illustrates the phenomena of tectonics in architecture in several ways.

First of all tectonics is about construction. Tectonics is the art of construction in architecture. What make a building remarkable entirely by way of the construction of the building? What makes the construction affect that special building so that people will recognise it? The homogeneity in the material of the cards and how they are put together represents an important tectonic aspect of the card house. Aesthetics in a homogenous material and structure are important when you refer to a tectonic building. The meetings between different materials and different parts of the structure are important here. How does the building hold together? As Adolf Borbein mentioned in 1982: “Tectonics becomes the art of joinings”

Secondly the “card house” has a hierarchy in its construction. From the bottom with its many cards to support the whole structure, further up to the two top cards at the top. Central in the ideas of hierarchy in terms of tectonics in architecture is Jørn Utzon.

“Utzon’s architecture may be read in terms of the separation formula of the earthwork versus the roofwork”. (Frampton p.260)

The idea of roof and platform and their different roles is interesting. The importance here is that the roof and platform are two different ideas, and it’s important that they play their role in the whole composition. The roof and platform are important in different parts of the hierarchy. More concretely: The heaviest part of the construction is the foundation, the walls are a bit lighter and the roof lies on top as the lightest part of the building. This makes common sense for every constructor and every eye in the world. In terms of Tibetan architecture this is of great importance, the typical Tibetan house is growing out of the ground, with a visible construction that is showing how the roof is supported.

The weight of one element upon another element and how these support each other is important. Light versus heavy. How one element holds another element in its place? Like in a card house as mentioned before. The weight of the horizontal cards strengthens the structure so that you can build higher and higher. Like an Egyptian pyramid. In modern architecture, architects can push these limitations further than the eye can understand. Of course with some help from engineers, some new technology

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and some governments with ability to pay. In many cases the result is very little tectonic; an example could typically be a Zaha Hadid project. In buildings where the form and façade are mainly held up by invisible constructions, everything is supposed to fly, and the real construction is hidden behind a membrane. Lastly the card house is a building system, that shows how the structure and the different “bricks” are readable in the construction. “.. It is true that a building, which is an agglomeration of units can achieve great intensity and unity, but this can only be achieved if the design of each unit anticipates the complex as a whole.” (Ibid p.509) The aesthetic of repetition in architecture is used a lot, and often gives some good results. But is this enough for a tectonic expression? Does tectonic architecture need to be a composition of one or at least only few similar components?

“Each stone is a stone, and from two you must not try to make a big one” Antoni Gaudi

You don’t want to make one big stone, but you want to make a coexistence of the elements so that they work together like a whole. The art of construction is of great importance here, because the most important thing in architecture is to construct a building with as few elements as possible without ruining the beautiful form.

APPROACHING THE PROBLEM:

“Tectonic structure before form or type must be a goal as a primer prerequisite for monumental form in architecture.” (Frampton p. 209-216)

In this essay I want to use two buildings of great monumentality to see if a proper tectonic concept is prerequisite for a good architectural result. Of course I also have to prove that the buildings are good examples of tectonic buildings. Is it or should it be an important concept for every project that the building’s tectonic idea is complete and clear?

The two buildings I will look at are the National stadium in Beijing also called “Bird Nest” and the National Aquatics Centre in Beijing also called “Water Cube”. The nick names are interesting from a tectonic viewpoint because they use the nature as reference.

First I will try to explain the buildings with focus on concept, function, construction and building process. Then I will try to prove or disprove if they are god examples of good tectonic monumental buildings. At last I will try to make a conclusion on the basis of both projects. Focus will be the tectonics in these buildings according to my understanding of tectonics related to the card house model.

“The material, detail and structure of a building are an absolute condition. Architecture’s potential is to deliver authentic meanings in what we see, touch and smell; the tectonic is ultimately central to what we feel....”

Steven Holl

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NATIONAL STADIUM BEIJING

“In China, a bird’s nest is very expensive, something you eat on special occasions.” Li Xinggang (CADG)

Built to the Olympic Games in Beijing 2008 the National Stadium in Beijing is one of the most iconic buildings making a trademark for the games. The architects behind it, Herzog & de Meuron from Switzerland in cooperation with China Architecture Design and Research Group (CADG), won the competition in April 2003, chosen as the best proposal in contest with 13 other firms. The construction and outside appearance were the main reasons for choosing the Bird Nest. “The building shape and structural design are perfectly consistent with each other.” (Jury National Stadium competition p.55) The bearing structure is kind of chaotic and it’s hard to see any system at all in the construction. The architects have taken the point of departure in a natural bird’s nest, where the structure is built up carefully piece by piece. A bird’s nest has no symmetric construction, but every branch depends on another. The bird’s nest is a truly tectonic piece of construction. The Stadium’s construction has however, contrary to the natural bird’s nest, some structural elements that the architects try to hide. “The structure appears to be a mess, but in fact the main bearing systems are very clear and reasonable.” (Jury, National Stadium competition p.55) None the less the architects have designed a type of building that has never been seen before. The Bird’s Nest is a visual trick, after all. (Steve Burrows, Arup)This mess of a structure constitutes the walls and roof of the stadium, and is independent of other structures. The whole structure is easily recognizable and therefore makes a great icon for the Chinese Olympic Games. Inside the outer structure we find the tribunes of the stadium, as a separate construction. The idea of separating these two structures creates a nice space in between where all the minor functions can be placed. This is where people move up and down and where commercial facilities and toilets are found. The architects were challenged not only in making a functioning stadium for the Olympic games: The architectural program focused also on what to do with the gigantic stadium after the games. How could this stadium become useful to the Chinese population as a public space? The huge roof construction, and the huge space between the outer and inner part allows for commercial use. Here hotel rooms with direct view of the pit and a shopping mall are planned. The stadium will be used for football and concerts after the games. As well as a place to visit for tourist, the Bird’s Nest is now one of the most known buildings of today.

The outer shell of the stadium is the world’s largest steel structure, and made from Chinese steel. The entire structure seems to be a perfect chaos at first glimpse, but actually there is a system. The bowl is higher on the eastern- and western stands than in the northern- and southern- in order to improve sight. The steel construction is built up by twenty-four trusses; every truss is weighing 1000 tons, which shows that the scale is huge. “We’ve got 24 columns that split into a V-shape on the outside. When the column gets to the fillets where the wall meets the roof, one beam goes off left and one right. Forty-eight beams crisscross the roof from 24 columns.

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If you stare at the building for long enough, you can see it all.” (Steve Burrows, Arup)As Steven Burrows mentions, the whole construction is a sort of optical illusion which seems more complicated than it fact is. Of course all twenty-four vertical V-shape trusses are strictly necessary, but the question is whether the many diagonal beams are really necessary. These beams make the stadium look like a highly irregular structure. Despite random appearance, each half of the stadium is nearly identical. (Steve Burrows, Arup) This statement confirms that the stadium has at least some kind of system. This is good from a tectonic viewpoint.

All the twenty-four trusses are touching the inner oval as tangents and thus forming the central opening of the roof. In this way they are all working together with respect to vertical stability. This is also the way of making a stabile bowl independent of extra columns in the middle. One other important design parameter is that every beam and column has the same external size. This is what makes the stadium a visual unity. As Steve Burrows says it: “In most buildings the columns and mullions are differently sized. It’s obvious to your eye that the big, heavy ones carry the load and the little ones hold the windows on. On the stadium they’re all the same size, so your eye can’t distinguish between the columns that hold the roof up and the ones that frame the windows. Make them all the same size, but only as big as they need to be.” This is important for the rather simple form concept, but it is hiding the “real” construction in such a way that it’s difficult to see which parts of the beams are really necessary and which are only visually important. The most important columns and beams are made in thicker steel than the columns and beams that are less important.

The structure is transparent, meaning that you can look directly through it. “The structure almost breathes,” says Jacques Herzog “We were aware from the outset that this was an enormous structure. We didn’t want this huge stadium to smother or repulse people, but desired the opposite: that it would attract and absorb people.” The only coverings in the structure are on the top, which is quite natural. The sealing is made of some thin, translucent material keeping the spectators dry. This grey material is mounted between the beams in order to not obscure the visual clarity of the construction. From the outside you can see that these coverings are “coming over the edge”, but they are only slightly disturbing. The transparency gives a feeling of life and openness to the stadium.

Diagram of the 48 beams in the roof.

Bird’s Nest under construction; the V-shaped column.

The V-shaped coulmn seen from outside and inside, after the completion.

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The fact that the $423 million stadium was built for one-tenth of the amount that it would have cost in the West says something about Chinas capacity of building and of differences in culture, materials and wages. If we think of what huge amount of money this would be if built in a western country we can imagine that the construction process must have been quite complex. The prefabricated steel elements allowed the construction team to construct both the outer steel frame and the concrete grandstands at the same time. This was in fact essential because there were time problems after some economic problems and change of plans, which delayed the project with almost half a year. The architects where therefore forced to make some adjustments and simplify the design to some degree.

NATIONAL AQUATICS CENTRE BEIJING

The competition for the National Aquatics Centre, built for the Olympic Games in Beijing 2008 was won by a constellation of PTW Architects, China State Construction and Engineering Company (CSCEC) and Arup.

The obvious concept of this building is clearly bubbles and water. The cubic form makes the naming easy; we have the Water Cube. As the competition for the “Bird’s Nest” was already over when the competition for the aquatics centre was held, the Water Cube could become an incredible good contrast to the big stadium. And when both have names from nature and have patterns and forms that appear random and organic these two stadiums make a perfect frame for the Chinese games.

The Water Cube achieves the wonderful, if somewhat coincidental, reality of becoming a building filled with water, made from a box of bubbles. (Tristram Carfrae, Arup)

The bubbles are all different and cover the walls as well as the roof; the building appears to be a blue box of shining bubbles in something that appears as an organic pattern. The structure seems unbelievable light and almost a little fragile. Fragile as soap bubbles, hopefully it’s more sustainable than it looks.

The Aquatics Centre is basically built around three main volumes. The biggest area is of course the main swimming pool with grandstands and diving towers. Secondly there’s one more swimming pool, without grandstands, for training and pre-training under the games and for public use after the games. The third volume is the lobby where spectators and other visitors enter the building. All volumes are cut out of the bubble construction, as I will mention later. Basic functions as changing rooms, restrooms etc. are placed under the main grandstands and on each side of the secondary pool. The construction of the envelope makes columns unnecessary; this gives the spectators full view of the pools. The transparent bubbles are also providing light and heating.

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From the basic concept of a blue box the architects had to find a solution of how to cover the box with something three-dimensional, with a uniform expression. The first solution was found in a thesis made by Lord Kelvin in the late 19th century. He asked what’s the most efficient way to divide space into cells of equal size with the least surface? And he came up with the 14 sided shape tetrakaidecahedron. This is however a rather uninspiring form visually, but the architects were now aware of the bubble concept and a dream was born. Our search for the most efficient way of sub-dividing space had led to a structure based on the geometry of an array of soap bubbles, clad with plastic pillows that look just like bubbles – to house the water at the heart of an aquatics centre! (Tristram Carfrae, Arup) The engineers looked on into the world of bubble physics, and found an efficient form in the Weaire-Phelan foam for the construction of the bubbles.

In spite of the Water Cube’s complete regularity at a first glimpse, it in fact looks totally random and organic when viewed from any angle. The Water Cube is carved out of an infinite array of bubbles looking like this Weaire-Phelan foam. The whole structure is 177m x 177m x 31m. The interior consists of three major volumes, which determines the geometry of the construction. The walls are 3,6 m thick, while the roof is 7,2m thick. The unique lightweight structure is build up of 3000 pneumatic EFTE cushions/pillows filled with low pressure air, inserted in aluminium extrusions supported by a lightweight steel structure. The EFTE is a tough recyclable transparent Teflon material weighing only one percent of an equivalent-sized glass panel. The structure holding the EFTE pillows are complicated and the engineers had to use a lot of computer calculations. There are over 22 000 different steel beams weighting 6,500 tons, joined in 12 000 nodes. As the roof is huge and have some long spans it’s critical that the construction is light and optimized.

The energy aspects were important for the architects as well as for the Chinese government, and that’s the main reason for designing a greenhouse like this. The choice of the EFTE material instead of one layer of glass is one of the aspects here. These EFTE cushions allow high levels of daylight into the building; swimming pools need a lot of heat. The sustainable passive heating produced by this reduces the swimming pool’s energy consumption with 30%. The use of thermal mass heat storage ensures that the heat the building gains from the sun during daylight is offset by overnight cooling. The thermal mass of the pool water and heavyweight surfaces surrounding the pool effectively stores the excess heat during the day and re-emits it at

How bubbles interfere together.

The 14 sided shape tetrakaidechedron.

The Weaire-Phelan foam, and how the water cube is cut out of it.

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night, minimising variation in load. That means that most of the solar energy that goes through the buildings structure can be captured to heat the pools and interior areas. Variation in shading of the facade has ensured that fabric heat loads are minimised in summer but maximised in winter, when the solar sun is most beneficial. This is achieved by patterning the various layers of the facade with translucent painted ‘frit’ and by ventilating the heat out of the cavity in summer and containing it in winter. The positions and patterns of these translucent elements have been developed to respond to the daylight and the thermal requirements of the various building uses next to the facade. For cooling, air is circulated through the space between the outer and inner cladding; this gives a sustainable thermal effect.

Constructing the Water Cube depended on a lot of measurements in the computer, and as mentioned there were a lot of different steel beams to produce. China actually rejected Arup’s proposal of using some automated production machinery. Actually all 22 000 beams were cut out manually after spreadsheets. Quite many of the complex connection between the beams are different; therefore they had to make 15 000 detail drawings for the fabrication on site. All of these are of course made automatically by a computer. First of course the ground work was done, then the swimming pools and foundations. Then the whole thing was covered with the bubble steel construction. At last came the EFTE pillows inserted in the steel frame and inflated with air until they filled each frame.

The steel structure in between the different volumes. Supporting the roof.

The transparent roof.

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TWO STADIUMS, TWO CONCEPTS?

The two national stadiums described are quite different in appearance, but is it possible to find similarities between them. If I should try to express the tectonics in these two buildings on a basic on their similarities, it’s natural to take point of departure in the fact that both seem to have a random homogeneity in materials and that they both are kind of bowl-shaped independent of other constructions. With point of departure in my card house from the start of this essay I intend to find this out. First, does the whole construction depend on a cooperation of every single element? Is the construction a piece of art, is the building a united whole of interconnected elements? Are the materials homogenous? How do the materials meet? And how does the building hold together.

Both stadiums are a piece of art, something that never has been seen before. Both stadiums have a very visible construction, which is important for each structure. But are both constructions as efficient as possible as a structure where every element is important. After discussing the Bird’s Nest, I’m not completely sure that every steel beam is equally important as the twenty-four V-shaped columns supporting the roof. When do these not important beams transform into ornaments or some decoration, and is this the end of the tectonic aspect of the building? After all they are parts of the whole composition.

The Bird’s Nest is said to be a chaotic construction without any system at all. The truth is a bit different when I look closer at the structure. Yes, we can with some certainty say that not every beam is necessary to keep the stadium standing. Many are in fact there to hide the construction supporting the roof. The twenty-four columns supporting the roof and the beams holding the whole bowl together are quite tectonic when you look on the bowl as one element. But another interesting fact here is that the “unused” beams have the same external thickness and material as the others. This underlines the fact that the construction is a unity, and that everything is important for the whole stadium to stand. The fact that some of the beams are just a visual trick to get the attention away from the real construction is of course hard to swallow in terms of tectonics. But the outer bowl of the stadium is a unity in material and construction.

In the Water Cube the structure came from physical and technical formulas with bubbles as a reference. Here every “bubble” is calculated in a computer after a special system. Every bubble with its frame depends on the neighbour bubble in a way that holds the whole construction together. If one bubble is missing, the construction becomes unstable. Every bubble is part of the construction and every bubble depends on his neighbours to stand, at least if we look at the structure holding the bubbles in place. This is not quite the concept of a natural bubble; you can perfectly well destroy one of a cluster of bubbles without all of them exploding. But it’s quite hard to destroy some of the bubbles in the middle without destroying some of the outer bubbles. In this way nature gives us a lot of excellent examples of tectonics.

The use of materials is interesting in both buildings, in the Bird’s Nest it seems like the whole steel structure is one element. This is because the meeting between the steel elements is well hidden. It’s like the beams and columns melt into each other, this is to hide the real construction, and so to speak is not very tectonic. The chaotic beams and columns constitute one element of all members, and therefore is it hard to say that the

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Bird’s Nest is any better than other buildings which try to hide their real construction and try to trick people into thinking that this is just a technological building. But anyway the whole composition and the way all the constructions work together is tectonic, because the structure with beams and columns hold the whole roof up without help from secondary structures or helping columns. The bowl is one self bearing structure with same material and certain homogeneity in material. Everything sticks together.

The Water Cube has bubbles, all with the same character and material. The bubbles play together as mentioned before. The steel structures, which hold the bubble pillows on place, are all a part of a big puzzle. The steel beams are all joined together in the same way with 12000 nodes. Every steel beam is unique, and calculated by a computer; how does this work with the tectonic thoughts? Of course the building is tectonic in the way it’s constructed from a physical theorem. But is this readable in the building without reading it in a book? Probably not; it’s hard to understand how it’s constructed. But bubble upon bubble is easy to understand, and you can see that they all are of the same material and character. All bubbles are part of the structure in an outer and inner shield, and it seems logical that they hold up the roof as a part of a big homogenous structure.

What about hierarchy in the buildings? Is it possible to separate the foundation, from the wall and the wall from the roof? Or is this really important in tectonics? None of the buildings have a lot of hierarchy in their construction and look because the wall and the roof are actually appearing to be the same. As described before the wall becomes the roof, especially in the Bird’s Nest. The only difference here is that the roof covers the steel construction. But the architects try to hide that the cover is thin and have almost the same colour as the steel structure. When we discuss hierarchy here there is more a discussion about the functional differences and the fact that the outer shell actually is a shelter, which in fact has a lot of qualities in ventilation and light and as a cover from rain. The grandstands are inside and another element, in fact I want to compare it to Utzon’s roof and platform. The Bird’s Nest steel structured bowl is in fact the roof. The platform is the grandstand and the pit where all the games take place. In this way we see the art of construction to take part in the building without affecting the tectonic premises of hierarchy. And in fact we find the exact same thing in the Water Cube; the swimming pools and grandstands are not in touch with the outer shell which again is roof and platform. The bubble box or the Bird’s Nest’s roof is in fact a need, a climatic shelter. And the architects have managed to make it an art of construction. The fact that wall and roof is the same doesn’t ruin the tectonic dream, in fact it’s quite logical to make all in one when you consider aesthetics and form. Especially when you want to make a form that is recognizable and iconic. In the same way, we can se that the traditional card house is made of one homogeny material which is placed on the platform which is the table. But it’s not tectonic if you consider the fact that especially the Bird’s Nest steel beams seem to grow out of the ground, with no platform at all.

The meet between roof/wall and platform in the Bird’s Nest.

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The last aspect from my card house is readability and the art of repetition. This is quite interesting in these two buildings.

The Bird’s Nest is as mentioned often a visual trick and therefore not readable as a tectonic idea in the outset. And because many of the beams actually are not important and only decorative, the building should be rejected as tectonic at once. But it has repetition; the twenty-four columns are repetition, the two sides are similar, that’s repetition and all beams and columns have the same material and thickness that is also a form of repetition. But everything is hidden in a huge structural visual trick, with the help of new technology and a country with resources and work power.

The bubbles stacked together are readable as an idea, and it’s obvious that they fit together in three dimensions. This becomes clearer when we look at the interior or at the section of the wall. We can se how the structure supports itself by distributing the forces in three dimensions. The bubble pattern is of course some kind of repetition and has a lot of homogeneity as mentioned before. The beauty of the same type of bubble forms placed together in a huge, cubic composition is nice. What we don’t know is how it all can stand; it looks like a quite light and weak construction. This makes it quite hard to read because this is a type of building, which we never have seen before. You can’t build a house with a bubble upon another bubble; they will break. The fact that it’s just an advanced greenhouse is also a little hard to understand. I mean it’s hard to understand how this could keep us warm, even if it’s sustainable and actually saving energy.

The question is now, what are the new technologies doing to the tectonics in today’s modern architecture? Where is the architect that is is concerned about detail and putting the house together in an extravagant way?

ICONIC TECTONIC, OR JUST SOME NEW TECHNOLOGY

“Nature has her materials of predetermined dimensions, and keeps to the same bricks whether she build a great house or a small house”

Thompson

New technology today allows architects to do many things, the more technology you find the less tectonic is often the building. Tectonics is about the art of construction and not the art of making buildings fly. I want to make the house grow out of the floor, that’s what building a house is about. And I want to make it a functional shelter with as few elements as possible where materials come together in a perfect way. The construction should be possible to track and see, constructing a house is what architecture actually is about. It’s a misunderstanding to hide the construction away.

New technology gives us a lot of possibilities and the two stadiums show how new technology can make the “wonders” of tomorrow. Mankind has to always push the line a little, more will have most and we need something that we never have seen before. China had the possibility and desire to do it this time; they wanted the games to make history. They might have achieved it, at least in their way. But can the new technology also be at help when it comes to sustainability and energy?

Is this the way the new tectonics should be focused? Of course in cooperation with good and innovative design, the results should be great form and beautiful buildings.

I have described two iconic buildings with a building process where computer technology was absolute necessary. The engineers and architects worked close together to construct structures that where never seen before. And the computers measured and gave the workers drawings and spreadsheets. But did they end up with an architectural tectonic wonder?

The Bird’s Nest is according to my opinion a tectonic building. The construction of the Bird’s Nest is a unity, and most of the beams and columns are important to hold the outer bowl standing. The construction with steel beams and columns in the same material and same external thickness play together as a piece of art. It’s art of construction. It’s still a fact that not every beam and column are important for the construction to stand, some are part of the composition to make the chaotic structure of the Bird’s Nest complete. Although these less important beams where made of thinner steel. In fact I will call these unnecessary beams decorative or ornaments. These beams/columns are a part of the entire structure; they make the real bearings difficult to spot. The real construction is in fact quite easy to see if you stare at the building long enough. I don’t think ornaments exclude the possibility that a building has tectonic qualities. The ornamented frames around many windows for example are not always a very tectonic requirement. In this case the ornament even looks like a part of the construction and make the architectural form spectacular. The extreme construction and size, underlines the fact that this building is a constructive piece of art, and in this way the National Stadium in Beijing achieves the status as an icon as well.

The technology is even more in the centre when speaking of the Water Cube. The construction is impressive because it seems like a bunch of totally random “bubbles placed on each other. The nature of bubbles and the clear intention of making them three dimensional by letting them express the entire structure inside and outside; makes the Water Cube easy to understand and logically built up. This is underlined by the very visible structure and construction. You can literally see trough the whole façade, you can see the whole structure and almost understand it because it’s one of nature’s phenomena. The fact is that it’s a unity as a shielding structure with roof and platform as in the Birds Nest, and again that the construction is something that never has been seen before makes the National Aquatics Centre a tectonic building. It’s also environmentally good and sustainable and a good example of that new technology can create constructive art in buildings. The easy readable concept of bubbles and a smashing name makes also the Water Cube to an iconic building, mostly because of its construction.

Both buildings got their names from the nature because of their innovative construction. Constructions which the world never have seen before, and even constructions highly visible for everybody. New technologies made this possible, because it’s not quite projects that you make every day. China wanted some iconic buildings, and they’ve got them through two projects telling a tectonic story of constructive art.

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SOURCESTektoniske visjoner i arkitekturen, Anne Beim (2004)

Studies in tectonic culture, Kenneth Frampton (1994)

DETAIL magazine #7-8, 2008, page 771-779

National Stadium Beijing – Presentation of the competition. (2008)The Beijing National Stadium – Engineering

http://www.architectureweek.com/2008/0827/building_1-1.html

The Beijing National Stadium - Architecturehttp://www.architectureweek.com/2008/0820/building_1-2.html

The Beijing National Aquatics Center http://www.architectureweek.com/2008/0430/tools_1-2.html

Water Cubehttp://www.arup.com

“Architecture comes from the making of a room”L. Kahn