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XXL Workshop_2011


0. Introduction 1. Drawings 2. Individual reports

2.1. Architecture report_B.A.van Walderveen

2.2. Structural Design report_P. Raghunath

2.3. Construction and Cladding Design report_M.Munoz Catalina

2.4. Digital Design Management report_E.R.Boer

3. Sustainability 4. Adaptability

INTRODUCTION A challenging social approach. Building through contrasts, interaction and integration. A combination of scales by integrating social housing and a stadium within a public space searching for a two-way benefit and keeping the area alive 24/7.

A urban approach. Designing from the context. A development oportunity.

The bowl. An imposing giant for the surroundings

The gesture: Integration throgh the continuation of the urban fabric. A strip which twists and wraps the bowl.


Daylight and permeability: The lower tier of the stands is removed to increase daylight in the cavity and facilitate the permeability of the space creating the illusion of floating when looking from the square.

Structural dependency: The light housing wrap supports the heavy bowl.

Inhabiting the twist. The introduction of the human scale.


Coexisting in the wrap: The stadium functions are integrated in the wrap letting the cavity between this envelope and the bowl remain open. The biggest gesture of this decission can be seen in the two walkarounds connecting through bridges to the stand´s tiers.

The cavity under the stands: A continuous public space.

Stands reconfiguration: Adaptability to different scenarios: football match and public space.


A public-friendly stadium


West public square and main entrance

south east-side entrance




27 21 12

Section_during football match

Section_a public space


Construction Housing

Dressing rooms VIP reception

Retractable stands

Retractable fence

Visitors staircase

Housing elevator

Housing staircase

ground floor plan


Walkaround/runningtrack Housing

Closable gate

Visitors staircase Housing elevator

walkaround floor plan

ARCHITECTURE REPORT_Bart van Walderveen Introduction In the initial assignment (XXL Workshop, design and research guidelines), the role of the architect is described: “ The tasks to be achieved during the process can be summarized as following analysis and understanding of the whole architectural program of the project; conception and development of design concepts; iteratively looped assessment/evaluation and review of the design considering the architectural performances (visual/aesthetic, functional, adaptable, sustainable, etc); integration of interdisciplinary aspects into the whole design from the very early conceptual phase and during the entire design process “ The architect of the project is clearly concerned with the ‘whole picture’. He should keep track on the different activities of the group-members, have a clear vision of the direction of the project, compile all the different inputs to one project, in which all the disciplines are combined. It almost seems like the architect has to put the other disciplines to work: he tells the structural designer what to calculate, he tells the cladding expert what image to strive for, and the digital design manager which parts of the building to investigate with computational power. The reality was much more diffuse. As the architect I was concerned with all of the three other functions a lot, but most of all with the computational design manager. From the beginning we tried to let the computer find our geometry for a large part. Although we did not completely succeed, the result was a design that was heavily based on (at least to me) new methods and possibilities. In this report I will explain parts of the process that we went trhough. Also a brief overview of the concept and the organisation of the plan is included, and finally a evaluation on the proces.

Table of Contents Concept Daylight based design Twist geometry Organisation Evaluating the proces

2 5 11 13 18

Concept The urban analysis In the week after the second presentation (the presentation of three concepts, week 3), the basic concept was born. Because the concept is directly related to the urban analysis that we did before, this urban concept is explained first. The first part of the urban analysis is a short investigation in the social-economic situation of Rotterdam-South. The maps on the right show three different topics. Income, unemployment and owner-occupied housing. The area for the new stadium is in the dashed red line. What stands out is that the stadium area is white in all cases, and the area east of the stadium is in a better condition than the area west. Another remarkable thing is the void directly left to the stadium area. This void contains a big road and a railroadtrack. This big barrier blocks out any effect that the new sportspark will have on the disfunctioning neighbourhoods in the west. In a more schematic way the conclusion could be the images below: The green part is the more or less well-functioning part, the red part is the area with a bad social-economic status. The big dark line is the spatial barrier the cuts the area in two parts. Ring in the centre is the old Kuip.

Schematic representation of the situation of the stadium area

Figures derived from

Concept We wanted to make a stadium in a way that it is really clear that there is a spill-over effect. There is a lot of talking about how the poorer parts of Rotterdam can benefit from the new stadium, but most of it is very vague talking about creating jobs and long term trickle-down effects. One of the first things to do is to establisch a fysical relation between the stadiumarea and the poorer areas. The big barrier should be reduced. In the masterplan we did this by just creating a lot of bridges over the tracks, and by making straight connections to the stadium area.

The green area on the left is currently a green space. Because it is next to the railwaytracks and the big road, the quality of this space is not very high. It is a great place to make parkingspace. The people that park their car there are forced to walk through the area. In this way there will be interaction between the match-visitors and the surrounding area. It will increase the opportunity for locals to exploit the new activity in the neighbourhood. Small shops, kiosks and catering will have more opportunity to survive.


Concept This masterplan was made in order to get a grip on the assignment. But also after doing this analysis we had too much parameters to adress. We decided to go with a really literal translation of the concept. We literally embed the stadium in a housing project. We extend the existing urban fabric, and wrap it around the stadium. The housing becomes a lasso that pulls the stadium towards the social-economic weaker parts. The flat slabs twist to vertical, the vertical part is surrounds the stadium. There are multiple arguments for the wrapping. First of al it is a big gesture. Everybody who sees it, will notice the relation between the neighborhood and the stadium When there is no match, the pitch can still be used by the community that is living inside the stadium. A quick calculation tells us that there potentially is place for over 1000 dwellings. Creating a social housing program in a well functioning neighborhood, segregation in the city will be reduced. By creating social housing here, disfunctioning neighbourhoods can be upgraded with private-sectore housing. We overcome the scale-difference between stadium and surrounding housing. Also there is no danger of the stadium becoming a ‘white elephant’. It gives a lot of interesting opportunities to do research. The combination of housing and stadium is a rare one. We couldn’t find a project that did this, exept for a conceptual design for a Handball-stadium by BIG.

Envelope of wrapped housing

Overcoming the difference in scale

Daylight based design The largest part of the time went to the organization of the wrapping. Because it is quite a hard geometrical shape to work with, we divided it in three parts: the flat part, the twist and the vertical part. A lot of time went to the rendering of the flat part. In the conceptual image on the previous page it is displayed as a solid mesh. This is obviously not the case. It is supposed to be smallscale dwellings with high density, within the envelope as displayed on the conceptual image. Because the flat parts are approximately 10 meters high and 50x70 meters (they are not the same size though), daylight will be the most critical factor in the placement of the dwellings. With the help of newly-discovered tools such as the Grasshopper-Geco-Ecotect combination, we tried to figure out a good solution for the rendering of the flat part. I will try to explain how we used the tools to create an optimal rendering of the flat part, and will evaluate it in the end.

Flat part, twist, vertical part

Assumptions and startingpoints We used the computer to optimize the form. However, this isn’t as easy as it seems, as the computer cannot think for itsef, obviously. That’s why we set a couple of preconditions and constraints, in order to reduce the solutionspace. The constraints of rendering in the flat part were the following: -

From an architectural point of view, we wanted to keep the visual appearance of one big slab. (1) The houses should all be accessable (2) The houses should, more or less, be evenly spread, i.e. there cannot be big differences in density in one layer (3) The size of the house is prefixed. They should be bigger at the ground floor than at the top, in order to have different social groups in the project (4). We only take into account indirect daylight (daylight factor) (5).

Especially condition 5 is questionable. This choice is made for pragmatical reasons. The software that we use is not able to take into account both direct sunlight and indirect daylight in one calculation. When we do an optimization for both of these simultaniously (they can be calculated apart), it is expected that we get two different outcomes, in that case a trade-off need to be made. Better would be a multi-objective optimization, but the software that we have is not sufficient for this. So we chose indirect daylight (skydome illumination), since it will be the biggest source of light on the ground floor.

random configuration within the constraints

Daylight based design The process scheme for the calculation of one layer is displayed on the right. The daylightcalculation is from a different configuration then the other ones, but the principle stays the same. In this case only one layer is calculated, but in theory all the three layers should be cacluated in the same time. In theory this model works fine. It is based on the assumption that the individual voxels (‘islands’) influence each other. Therefore it makes no sense to calculate one voxel and repeat that pattern over the rest of the islands. To test the assumption, we did calculations for only two islands. If our assumption was right, the optimal solution should not give two exact same islands. We let Galapagos run (on which later more). And indeed, the optimum was as we expected. It placed the main mass on the most outward edges. This way they interfere with eacht other as little as possible. Note that we removed the walls. This corresponds with 100% transparant glass. This way the potential daylight is measured. Hence the relative values are useful, but the absolute values are not. However, since this is an optimization, the relative values are much more important.

Define shape

Define streets

Define voxelsize (2x2/3x3/4x4)

Define shape

Define density

Calculate average daylight factor Define streets/islands

Optimization for 2 voxels. The geometry shows interference

With the testing of the two islands, a major flaw was revealed. The outcome of the optimization is to a heavy degree dependant on the accuracy of the analysisgrid (the colored plane). If the number of subdivisions of the grid is enlarged (i.e. the accuracy enlarged), the outcome will be as expected. However, when the grid resolution is too low, the results will be way off. The consequence is that, in order to get good results, the gridresolution must be relatively high. This obviously adds to the calculation time.

Define voxelsize (3x3)

Using Galapagos to seek for geometry In the first builds of the model, we used the RandomReduce command in Grasshopper. It randomly removed blocks from each island untill the desired density was reached. By using different randomseeds, every island got its own geometry with the same density. This way, a random solution is generated. The daylight factor of a random solution can be compared with other random solutions, and the best can be stored throughout the proces and replaced when the program finds a better one. This process is basically a brute-force algorithm. Its about the least effective way of seeking for good solutions.

Calculate daylight (Ecotect)

Define density (5 out of 9)

Daylight based design Connecting the model with a genetic optimization algorithm would be much more useful. However, Galapagos can not handle the model in its current form. The geometry is based on the random seeds of the RandomReduce command. It is easy to understand that connecting this seednumber to a numberslider won’t make much sense. It has no ordinal scale. When Galapagos tries to make small mutations on the numberslider, it will result in completely different solutions. So we needed to find a way to let Galapagos make small mutations in the geometry. In this way, the genetic algorihm can do it’s job. It can create mutated offspring from the fittest solutions, and converge to a good solution relatively quick.













One way of doing this is remapping the 3x3 (or 2x2 or 4x4) voxel into a binary number, and converting this number to a decimal. This decimal is stored in a list, that is connected to a numberslider. The process is displayed on the right. Because we used VB to script, this proces was very fast and added basically no time to the calculation. In the example to the right, some options of a ‘4 block configuration’ (4/9 density) are displayed.







Simple combinatory learns that within a 9 bit number 511 different solutions could be generated. Out of these 511, 9 nCr 4 = 126 combinations are ‘4 block configurations’. When we take the decimals of these configurations, and put them in order, we get this list:







This list can be connected to a numberslider. Below are the first solutions of the list. As you can see, the changes are minor: for each increment, a maximum of 2 bits are swapping position. Now Galapagos can more or less seek in a direction. We removed the Random element. Of course there still are a lot shortcomings in the model (e.g. the big leaps between bitnumbers such as 15 (1111) and 16 (10000)). But quick tests show that Galapagos is able to converge to solutions.













One island, 9 digit binary number

Configuration that corresponds with no 011001100 (=204)

Configuration that corresponds with no 000001111 (= 15). This is the ‘lowest’ 4 blocks configuration

Configuration that corresponds with no 11110000 (=480). This is the highest 4 blocks configuration

Daylight based design Now the model is ready to be connected with Galapagos. Each individual island is connected to Galapagos as a genome. This way they can be changed independently. In theory this model works fine, and we tested it with low resolutions with a limited amount of islands. However, the calculation time for the total was extremely high. It was so high that it would take weeks to optimize the ground floor alone, withouth taking into account the upper floors. We either need a supercomputer or a faster way of calculating daylight factor. Because the Ecotect calculation is the big bottleneck in the proces. It seems like we have to conclude that with the current state of software and hardware, it is not yet possible to do a direct optimization on this scale. This was a huge letdown. In theory the approach works, but in reality it fails to do the job. While this was disappointing, it was a good moment to evaluate the sense and nonsense of such optimization processes.

The makeshift solution Because the previous approach did not lead to geometry, we used a different approach. We needed to move on in the process. In this new approach, Ecotect was completely skipped. We did some rough assumptions that are probably not very accurate, but as a provisory solution good enough. The assumptions were the following: -

All islands individually connected to galapagos

In order to get as much daylight in, the amount of blind walls on the ground floor (‘back to back walls’) should be reduced as much as possible. (1) Streets are very small, and the daylight coming in by the streets should be reduced o completely disregarded. (2) Since the density of the upperfloors is lower, daylight on the ground floor remains the variable that needs to be optimized. (3) In order to get as much daylight to the ground floor, the overhang of dwellings should be reduced as much as possible. (4)

The image on the right shows a quick optimization for the ground floor. The conversion of islands into binary and decimal numbers is still needed. As you can see, Galapagos is able to converge, but the decreases in average sometimes show that there are flaws. This can be either due to the relatively small population-size, the flaws in the conversion process (as described above) or Galapagos using a weak algorithm or a pseudo-genetic algorithm.We did not investigate this further.

reducing blind walls

The calculation of overhang was initially done using boolean operations. It is possible to measure overlapping faces, and optimize this number. However, boolean operations are very heavy operations. Therefore we decided to use the project command. The edges of the overlying floors are projected on the roofs of the underlying layer. This amount more or less [sic] is related to the overlapping area, but the process is much faster and therefore much more suitable for optimization. In the image right the result for this optimization is shown.

reducing overhang

Daylight based design Evaluation The result of this makeshift solution can not be called optimal. On a meta-level, the only claim we can make is that it is not the worst solution possible within the given set of constraints. In hindsight we can conclude that the way we approached this, showed some major inconsistencies. The most obvious one is that it is a layer by layer approach. When the ground floor is optimized without context, we bake it, and use it as context for the other layers. There is no iteration of the whole. The process is described in the flowchart below. A better approach would be an approach were the whole geometry would be adjusted, based on Generate multiple objectives. In the scheme on the right, ground floor an example of a pseudo-multi objective algogeometry rithm is displayed. Blind walls and overhang are both evaluated in the same process. Because Calculate these variables are different units of measureamount of ment, they have to be converted to the same blind walls scale. This can be done by manually give them a certain weight. Galapagos: no Solution Create However, this is not truly multi-objective. If we sufficient? mutations had to redo this, we probably would have used an algorithm that is more state-of-the-art than Galapagos, and are capable of considering yes multiple variables for fitness. It would be quite a challenge to design this part of the building Generate first and take not only into account the daylight, but floor also the things that are now constraints. Such as geometry connectivity, structural feasability, direct sunlight and density.

Generate ground floor geometry

Generate first floor geometry

Generate second floor geometry

Calculate total amount of overhang & total amount of blind walls (2 objectives) Evaluate solutions by giving predefined weight to both objectives

Not sufficient

Galapagos: Create mutations



Pseudo-multi objective optimization flowchart

Calculate overhang

Solution sufficient?


Galapagos: Create mutations


Repeat for second floor Used approach

Render of ‘optimized’ configuration

Daylight based design Floorplans The strategy for the further development of the houses was also a based on the daylight. The basic idea is to caculate a lightmap, and look for the zone in the indiviual dwellings where the most potential daylight is. This part of the dwelling will contain the light-sensitive functions such as the livingroom. The dark functions are clustered and placed in the darkest part of the building. These functions are mostly the bathroom, toilets, part of the sleeping room(s) and storage. We made a quick sketch of possible options. Although we did not elaborate further on this, it would be a great idea to have all the floorplans generated parametricly, based on the dark and light spots in the room.

light calculation from ecotect


floorplans based on lightmaps


dark box sketches

Twist geometry The twisted part is a hard geometrical form to use as functional space. The first rendering of the twist was just a 90 degree rotating of the flat slab. The image is displayed on the right side of the page. The render shows that all the floors are sloped. In order to avoid this, we regarded the twist more as an envelope. Within this envelope we filled in as much usable space as possible, as schematically displayed in the image below.

In order to achieve this, the twist is sliced up in 5 meter wide slices (the same width as the dwellings in the vertical part). The result of this operation is displayed on the right. When you do this straightforward, a lot of space within the envelope is lost. The defenition of useful space is: space that has the full height (3m) and is deeper than 4 meter. So what is visible on the middle image on the right is that the ground floor is immediately discarded. The heigth of this floor is lower than 3 meter, albeit only a few centimeters. So in this way a complete floor is lost. Because of this non effecient way of rendering in space, we tried to find a way to do it more efficient. By offsetting the first floor from the ground, the total floorspace will change in the slice. It is displayed below:

First twist render

Removal of unusable space

View from inside

Twist geometry This proces can be plugged into Galapagos, and so an optimal offset from the ground can be found. The result (before and after) is displayed below. As you can see, all the floor are shifted

compared to the next ones. The gain of floorspace is about 11%. Its a significant amount, but with these shifted floors you create a lot of problems. There have to be numerous staircases, and in addition to that, the visual clarity is lost for a large part. A last problem that you generate with this system is the open space underneath the twist. It is too low to use it, so there is a danger of creating a place were the cleaners cannot come and dirt will accumulate there. All these considerations led to the conclusion that in the end we would be better off if we returned to the ‘unoptimized twist’.

Connecting the twist and the flat part During the process, we used a different workflow and different grasshopper-models for the twist and the flat part. This resulted in different visual styles. The connection between the two was initially a very clear line as shown below.

The transistion between the two parts have been done manually. The result is aesthetically OK (shown on the right), but it lacks a clear idea. The only clear parameters are the streets which have to be connected to the vertical part of the building. This streets split up the solid mass of the twist, and are causing the same pixelated look as the flat part has. After the streets were drawn, some of the houses were removed in order to get the same density and daylight as the dwellings in the flat part. The result is good, but it lacks a real systematic approach.

pixelated dwellings

Organisation In the building there are two main groups of users. There are the inhabitants of the building, whose amount will be around two-thousand, and there are the match users. This will be mainly the visitors (70 000 max), the players and the VIPs. Because we placed all the functions of the stadium (besides the stand and the pitch) in the vertical part of the wrap, there is a potential conflict between the visitors and the inhabitants. We tried to adress this problem as good as possible.

Inhabitants The routing through the buildings for the inhabitants is displayed below. A couple of close-ups are made for typical spots. There is a pedestrian network throughout the whole building. It is possible by multiple ways to enter the vertical part by the twit. In order to leave the building, people can choose either to take the stairs or walk down the twist. The rings hat are during matches in use as a walkaround are used by the people. The lowest walkaround is actually a running track were people can run an have a view over the water.

Flat part


Vertical part

Organisation Match visitors


The main entrance is at the square-side. This square is dimensioned on the big flows of people that have to pass by. In order to avoid the situation of visitors entering private space and galeries, a retractable fence makes a seperation between the area were visitors can come and the area were they cannot come. This line is the dashed line. During the match, the connection between the walkaround and the twist is closed down. This is also to prevent the visitors to wander around in the alleys and streets of the project. Note that the staircases for the stadium are different then the stairs for the houses.

There is a relatively small parking space in the building. The parkingspace is for the inhabitants and the VIPs. There is a shortcut from the parkingspace to the skybox-ring It is located at the start of the first ring of stands, about 5 meters above the ground. THe gaps are aligned with the gaps in the stands, they are designed to let in more daylight in the cavity.

Skyboxes The skyboxes are between the two stands. They form a seperate wallkaround. This way the VIPs do not have to mix in the crowd.

ground floor walkaround retractable fence/security line elevated walkarounds/stairs


Ground floor

Construction Housing

Dressing rooms VIP reception

Retractable stands

Retractable fence

Visitors staircase

Housing elevator

Housing staircase


First walkaround level

Walkaround/runningtrack Closable gate

Visitors staircase

Housing Housing elevator


First walkaround level


Evaluating the process The facade During the process (read more in the report from the facade engineer!), the facade initially never became a integral part of the building. In the first sketches, there was a general idea of a facade that would follow the twist and become a roof. However, after a little research it showed that the facade as a roof just isn’t functional. Our cladding engineer came up with a different solution, the gradually dissovling of the twist. A render is displayed on the right.

gradually dissolving the facade, first take

Nobody was really satisfied with this facade, so we tried a way to do it more in the style of the building: a second skin facade on the vertical part, that pixelates in the twist and eventually disappears. In this way we wanted to give it the same random generated look as the dwellings have. Although this was a slight improvement, it still was not very convincing. The whole idea of the second skin facade was just not in touch with the concept. It was not necessary, and the sustainability properties were also not very convincing. Three weeks before the final presentation we decided to drop it, and we decided that we want the facade as invisible as possible. The raw, pixelated concrete look is the most important image.

gradually dissolving the facade,second take

After this decision, the cladding mainly focused on the individual dwellings and the cladding on the dome. In the end it turned out nice, but it feels like we missed a chance there. Because our Digital Design manager was mainly concerned with the dark spaces in the caviity, it would, with the benefit of hindsight, have been a very interesting challenge to clad the inside of the cavity in such a way that it becomes a nice space.

gradually dissolving the facade,second take

Evaluating the process Parametric modelling In the beginning of the process, the fysical model was built in Grasshopper only. The parametric approach allowed us to do (more or less) quick changes in geometry. Especially with the exploring of the flat part of the twist, this was very useful. It was basically a key factor in the design process. The shapes were for a large part doubly-curved, and the number of repetition was so high (1000+ dwellings from the start) that it was essential to stay working in Grasshopper. Also for the daylight in the cavity it was important that we could make relative quick adjustments in the curvature of the vertical part. However, throughout the process, the parametric and non parametric modeling approachers started to be used next to each other. Most of the time it involved baking of objects, which then became rigid. The problem however was that most the geometry could not easily be described in euclidian forms. Making small adjustments, such as subdivisions or extrusions all of a sudden became a very hard task. The process involved a lot of iterations of the sequence of parametric modelling, baking, adjusting by hand, inputting the result back into grasshopper and continuing parametric modelling. In order to keep the different tasks and activities in the team coherent, it is very important that the core model is extremely clean and accurate. Otherwise the flaws in the model keep on expanding due to the above-described cycle. Especially in the last week, a lot of very sloppy modeling has been done, due to the timeschedule. The result was an very dense, heavy and inaccurate model. One should make the choice, either start parametrically and do as much as possible in a parametrical way, or decide to ‘bake’ from the start and lock the coordinates in AutoCad. This way the errors stay small, because there is a checkpoint. Of course there are different ways to have a streamlined process, but the workflow that we had was far from it. In theory every beam and column should fit perfectly, but to get it exactly right is a completely different story.

XXL_Structural Design report Prashanth Raghunath_sn: 4129253_group_1

Table of contents

1. Structure concept 1.1. Introduction 1.2. Evolution- process

2. Roof 2.1. Introduction 2.2. Sections and loading 2.3. Iterations 2.4. GSA analysis

3. Housing and the bowl: 3.1. Introduction 3.2. Sections, Boundary conditions 3.3 Loading 3.4. GSA analysis

4. Construction techniques and further development.

Concept_introduction As a consequence of the urban analysis, we got to the main goal of our project: the integration of the stadium in the urban fabric. This integration was approached through a big urban gesture. The urban fabric would continue and twist in order to cope with the height of the stadium and therefore, build its context.

The wrapped urban fabric,i.e. the proposed neighbourhood around the stadium would help in sustaining the stadium. We explored the same idea structurally as well, the housing would literally carry the stadium, i.e. the bowl with its roof. A simple diagram which illustrates this is provided below.

As the project moved further and the architectural characrter for the project gained more strength, we had the walk arounds for the stadium happening along the housing ribbon. Pedestrian bridges connected the walk arounds with the bowl. We proposed to use these bridges as structural connectors too. Part of the load from the bowl would be transferred to these bridges which would in turn transfer the load to the housing structure.

The above diagram shows a graphic which we intended to achieve- A Clear functional and structural relation between the stadium and the housing. Regular column grid below the stands would ruin the idea and also we intended to create an atrium like space in the cavity between the housing and the stadium. Hence the lesser the columns, the better for our design it would be.

Concept_evolution- process As the project evolved there were several architectural ideas which triggered ideas for the whole structural system for the entire project: 1. The housing was more more or less modular and foollowed a certain grid, which led to the proposal of shear wall construction system for the housing, which would act as the main support for the stadium. 2. The bowl, inclusive of the roof, was seen as a heavy mass, which was being carried by the housing ( a more political statement), which led to proposal for having a concrete roof for the stadium as it would be seen as a continuation of the bowl. Thus it gave us an opportunity to explore how a heavy material like concrete could be best used to span such a stadum roof. 3. The functional bridges which connected the walkarounds in the housing ribbon with the stands. These were used as structural load transfer elementsa and as elements which provided lateral stability. 4. The staggering of the bridges for the lower and upper tiers helped in visualising a system of bracings carrying the bowl, the intersections of which embedded the trusses for the bridges. (Refer the process diagrams in the following sheet). The render on the right gives the isolated picture of only the construction elements isolated as finally conceived. The lateral stability which the floor slabs of the housing provides have been ignored in this image for better clarity. We can also see in this image, how the structure is treated slightly differently on the front side, because there is no housing there and its a plaza. Hence Inclined braced columns have been provided instead of the shear walls (refer pictures below also). The 2 staircase cores on each side of the front side also provide stability to the front part.

Concept_evolution- process The diagrams on the right illustrate the process of deriving the structure for the stadium. The yellow honeycomb sort of structure which is shown from the 3rd image are basically inclned planes originating from the housing shear walls which are used to determine the bracings for the bowl and thus the position of the trusses for the bridges as shown in the 5th diagram.

The figure below shows a rendering of the construction of a part of the stadium, by removing off the housing units for visualisation.

Roof_introduction We designed the present a feeling of being a part of the bowl itself and not as something which is put over to just cover the space below. The bowl being solid concrete, we decided to continue the material for the roof as well for unity. There were basic problems associated with this idea: 1. Concrete would cut off the light below 2. The dead weight of the roof would become too difficult to handle and not worth the effort. Hence we proposed perforations in the roof, more like coffers. The next development was to hav a gradient in these perforations, to gradually more from more solid to more void towards the inner ring. The solid ring beams, as they may be structurally called, would be hollow sections, to reduce the weight. The grid for the perforations originate from the housing gris, that is, they start off as 5m centre to centre at the periphery and gradually reduce as they move inwards. Every third or fourth radial member is connected to the housing shear wall according to its position. We also proposed to have light weight structural concrete, whose density varied from 14401800 kg / m3 as opposed to 2400 kg/m3 of regular structural concrete. After researching on the densities and the structural characteristics of the light weight structural concrete, we chose light weight concrete of the following properties: 1. Density: 1590 kg/ m3 2. Young’s modulus: 1.4E10 N/m2 (long term concrete) 3. Poisson’s ratio : 0.3 The roof would be clad with ETFE panels which would be discussed in the cladding chapters.

Roof_sections and loading Sections used: The table on the left shows the section sizes used for the ‘light’ concrete roof. 1. The first nine rows show the ring beams starting the bottom most one 2. the next eight rows indicate the radial beams abstracted as cut beams between the rings, varying in width from 800 to 500 Please note that the first five sections used are hollow sections. In reality, the first two of these supposed to be ‘hollow’ members have more diaphragms in the moddle for stiffening

Loads: L1- gravity load L2- wind under pressure @ (1.21kn/m2 x 0.7) L3- wind downward thrust @ (1.21kn/m2 x 0.7) L4- snow load @ 0.56kn/m2


Our first proposal for the roof had a difference in height netween the inner ring and the eave was only 7m as we dint want to hav the roof to be over emphasized from outside. This resulted in a deflection of 1600mm under gravity. Thus we were forced to increased to increase the height to 12m which reduced the deflection to 850mm. This was the first iteration.

After increasing the height, the roof still continued showing differences from what actally was expected. It was natural to expect that in a form that resembles a dome (with oculus), the compressive hoope forces increasing towards the inner ring. But this was not to be seen. The compressive forces were higher in a few middle rings. Professor Andrew Borgart suggested this might be because the ring beams had a lot of variations in the cross sectional areas due to our architectural requirements. He suggested us to just try the same structure with ring beams of same cross sections. We tried it and immediately the hoope started behaving as expected. Thus we modified our original ring beams, to be hollow enough to allow for similar cross sectional areas through out except for the inner hoope ring which was required to have a higher cross sectional area and reanalysed the model. It worked. The axial compression force was the maximum towards the inner ring. The hoope forces were clearly visible and domical action was seen. Refer the 2 images extracted from GSA for the first and the modified conditions.`

The first image below shows the roof with a more elliptical inner ring, which resulted in a deflection of 850mm under only gravity load. A slight change in geometry, as suggested by Andrew, to make the inner ring as close to a circle as possible, as shown in the figure to the bottom right and also a slight change in curvature, reduced the deflection to just 316mm. What a drastic change in deflection by only a small modification in geometry!!

Roof_GSA analysis Deflections:

The Roof was checked for deflections for 4 different load case combinations: 1. Only Gravity load (L1) The maximum deflection = 316mm. 2. Gravity + wind under pressure (L1 + L2) The maximum deflection= 266mm 3. Gravity + wind under pressure + snow load (L1 + L2 + L4) The maximum deflection= 299mm 4. Gravity + wind downward thrust + snow load (L1 + L3 + L4) The maximum deflection= 412mm

Maximum deflection is thus found in, quite obliously, where all the forces are downward.

Here we would like to mention that, in the initial proposal, where the inner ring was more elliptical, the maximum deflection was found in the mid span of the longer side, on the inner ring, because the ring was flatter there and dint function as a good hoope. After changing the shape of the inner ring to a more circular one, the maximum deflection was found along the radials in the corners towards the inner ring, due to the higher overall span.

Servicability limit state check: Maximum deflection should not exceed (Minimum span / 250) Minimum span= 188m Therefore allowed deflection= 188/250 = 752mm Thus the maximum deflection found is less than the allowable deflection. Thus we can safely assume that the roof structure is buildable.

Roof_GSA analysis

Reaction forces

Reaction moments

The major component of the reaction forces come from the dead weight of roof, which constitutes about 75% of the combination of (L1 + L3 + L4).

Again the maximum reaction moments happen at the supports of the filleted corners of the stadium which is about 45000kn-m

The maximum reaction force here is about 9000kN. The maximum support reaction happens at the support in the filleted corners of the stadium as the constitue the support of the longest span and hence carry the maximum load.

The design for the roof connectors are discussed later but given below is a rough check for the workability of the connectors. Depth of the shear wall below the roof connector= 8m There force transferred throught the connector to the shear wall due to the moment= 45000/8= 5625kN Average cross section of the roof connector= 300 x 1500 Therefore compressive stress taken by the connector due to moment= (5625 X 103) / (300 X 1500)= 11.11 MPa Maximum allowed compressive stress in concrete= 33 Mpa. Therefore the roof connector designed is workable for the moments obtained due to the roof

Roof_GSA analysis

Axial Forces: The above figure shows the axial forces along the members of the roof. The figure shows the net force with combined load cases of (L1 + L3 + L4). The radial members hav a uniform force distribution all around. These forces are more pronounced along those radial members which are supported at the periphery... i.e.. evry third member more often. The Ring members hav a combination of compressive and tensile forces. The compressives forces being the more evidently dominent of the two due to the domical character of the roof. The compressive reaches towards a peak of around 18000 kN towards the inner hoope ring. The middle rings hav approximately arounf 6000-8000kN of compressive force. Stresses: The axial force gradually changes reduces to zero in the bottom most rings. The corners however encounter a slight tensile force of about 3000kN. Hence probably the bottom rings have to be reinforced with extra steel reinforcement or steel plating has to be done.

The above figures shows the axial stresses along the members of the roof. The topmost figure shows the stresses with only gravity load case. The figure immediately above shows the net axial stresses with combined loadcases of (L1 + L3 + L4). The Ring members perfectly demonstrate the behaviour of hoope. We can see the compressive stresses gradually increasing towards the inner ring. Check for Ultimate limit state: Maximum stress observed= 16.8 Mpa Maximum compressive stress X 1.5 should not exceed 33 MPa ( precast concrete) Therefore allowed stress= 33/1.5 = 22MPa Thus the limit state stress found is less than the allowable stress. Thus we can safely assume that the roof structure is buildable. The combined stress, however, under the most critical combination of load cases, is 23.48MPa,(see figure to the left) which is slightly more than the acceptable value.

Housing and the bowl_introduction

The construction model created in Rhino, had to be broken down into a split segmented wire frame model which could be then plugged into the Geom gym application in grasshopper, similar to the way, the roof was done. For the purpose of anaysis, we chose only the rear half of the stadium for analysis. There were two reasons for this: 1. The relation between the bowl and the housing was more established in the rear half as the front part doesnt consist of the plaza, and the roof rests on inclined columns braced with each other. 2. The front part had difficulties in splitting up the elements along all the nodes for the purpose of taking into GSA, as the structure transformed from the housing shear walls into inclined columns gradually and the truss bridges connecting to them couldnt be modeled perfectly with the available time. We thought this would suffice for checking the workability of the proposed structure. The wireframe thus built in rhino was transferred into the geomgym plugin for grasshopper to be taken into GSA for further analysis. There are a few assumptions made due to lack of skills which we like to mention: 1. The shears walls for the housing are simpliefied to be deep columns, as the surface modelling for GSA proved to be too complicated within the available time. 2. Additional lateral tie members are added at the points where the roof sits to replicate the lateral stability the roof would provided if modeled together. Unfortunately since we modeled the roof independently for GSA, these non- exixtent tie members had to be provided for analysis. 3. Since the wireframe lines of the shear walls (deep columns here)are taken along the inner edge of the housing, to keep the connection between them and the trusses intact for analysis. This resulted in an offset of the inner edge of the shear wall within the cavity by 4m. We hope this isnt a major factor which can totally change the results obtained!

Housing and the bowl_sections, boundary conditions

The following table shows the various elements and the section properties assigned: Element


Section type

Width Depth Dia mm mm mm

Wall thickness mm

Bowl Inner Columns Bowl outer columns Main beams, diagonal braces Lateral ties Roof connectors Shear Walls

Concrete Rectangular- solid



Concrete Rectangular- solid



Concrete Rectangular- solid



Concrete Rectangular- solid Concrete Rectangular- solid

450 300

900 1500

Concrete Rectangular- solid



Floor slabs of housing Truss flanges

Concrete Rectangular- solid




Ciruclar- hollow



Truss struts


Circular- hollow



Boundary conditions: 1. All the columns and the shear walls are clamped at the ground level. 2. The arched opening at the rear corner is clamped at the ends. The arch itself is analysed as a heavy, steel compression member Since the bowl is cut into half for analysis, we provided restraints for the nodes along the cut section, in order to compensate for the stability lost due to the removal of the other half.

Housing and the bowl_loading Loading: The loading of the bowl is abstracted as point loads on the nodes of the bracing, as surface modelling of the bowl seemed too complicated in GSA. The lower tier is less deep than the upper one, approximately 70% the depth of the upper tier. Slab thickness assumed for the bowl is 600mm, considering span to depth ration of 25 for a span of 15m per bay. Live load on the slab is assumed as 3.5kN/ m2. Flooring, furniture load is taken as 1kN/ m2 The lower tier is abstracting to be supported over the nodes indicated in the figure on 2nd figue to the left, assuming a cantilever of the slab both towards the slab and the bottom. The upper tier is again abstracted to be supported over the nodes indicated in the 2nd figure to the left but this one being supported at its ends on the top and bottom towards the end of the bracings at each side. Considering all these factors, the net nodal loads we get is 3500kN per node along the lower tier, and 5000kN per node along the upper tier. The upper most nodes also carry the load of the roof along with the bowl. The roof analysis gave a maximum reaction force of 5000kN. So this value has been added on to all the upper nodes. Hence the upper nodes hava an effective loading of 10000kN. (see table on the bottom left). We tried to give moments from the roof also as nodal loads for the upper nodes, but we couldnt achieve to do this as we couldnt figure out the method to give orientation of the moments for each node along the curve. This was because the nodal loading always takes global co-ordinates. Hence the analysis carried out, unfortunately, is without the moments generated from the roof, which has a maximum value of 45000kN-m. We assumed this gets carried by only the roof connectors and the housing shear walls and does not really affect the performance of the other parts of the structure and proceeded further.

Housing and the bowl_GSA analysis Deflections:

The entire structure was checked for deflections for only one load case combination: L1 + L2 which consists of 1. Gravity load of the frame itself (L1) 2. The load from the bowl including the live load, and the load from roof, all abstracted as nodal point loads (L2) The general maximum deflection for typical bays is 75mm One critical point over the rear arched opening deflects 166mm. Hence the arch and twist hence needs to be treated differently.

Servicability limit state check: Maximum deflection should not exceed (Span / 250) Span= 15m Therefore allowed deflection= 15/250 = 60mm Thus the general maximum deflection of 75mm is slightly more than the allowable deflection. Thus we need to stiffen truss members and the upper diagonal braces, by increasing their diameter and depth respectively

Housing and the bowl_GSA analysis Axial Forces: The figure on the left shows the axial forces in the members with the combined load cases (L1 + L2). As one can see, the compressive force in the huge arched entrance is extremely huge and it almost makes sure that no other axial force is actually noticable.

Axial Stresses: The figure on the left shows the axial stresses in the members with the combined load cases (L1 + L2). As one can see to the left, due to the combination of concrete and steel used, steel being used only for the trusses, the highest stresses are seen in the steel members. The stresses in concrete is hardly noticeable due to this intense variation in stresses. The diagram gives an overall picture but the stresses are more prominently seen in the blown up part of the corner, shown in the subsequent sheets.

Housing and the bowl_GSA analysis Deflections- part segment blown up :

The general maximum deflection for the concrete element is about 75mm The general maximum deflection for the truss element is about 91mm

Servicability limit state check: Maximum deflection should not exceed (Span / 250) Concrete element: Span= 15m Therefore allowed deflection= 15/250 = 60mm Thus the general maximum deflection of 75mm is slightly more than the allowable deflection. Truss element: Span= 16m Therefore allowed deflection= 16/250 = 64mm Thus the general maximum deflection of 91mm is slightly more than the allowable deflection. But we feel these deflections can be sorted out by changing the section thickness and sizes and overall the structural system is workable.

Housing and the bowl_GSA analysis

Axial forces- part segment blown up : The figure on the top left shows the axial forces in the members. Here we can see that maximum load is going into the housing shear walls because the roof is also resting over them. And this is clearly what we wanted to achieve also. But the astonishing thing is the diagonal braces carry tensional axial forces. But since these are beams, bending forces also add to the principal stresses. Axial stresses- part segment blown up: The figure on the left and on the top show the axial stresses in the members. Again, since steel members are thinner and carry more more stresses, the stresses in concrete is hardly noticeable:

Ultimate limit state check: Maximum stress observed in steel= 250 Mpa Maximum compressive stress X 1.5 should not exceed 460 MPa (High strength low carbon steel) Therefore allowed stress= 460/1.5 = 307MPa Thus the limit state stress found is less than the allowable stress.

Construction techniques and further development As the design progressed, we rejected the idea of artificial grass and proposed to have a sliding pitch. So the pitch sliding out towards the rear side ( east side) presented a structural challenge in terms of having the housing over a free span of 70m. Since the housing was a contimuously framed box structure, we thought of treating the entire housing itself as a high beam, taking advantage of its height which is 8 floors or 24m. So we propose to hav steel framing in the houses which intersects along the principal stress curves of this ‘beam’. These triangular frames are placed in the middle of each of these houses, inducing a different kind of configuration in these houses. Refer figure below. The bowl could probably spanned by further splitting up the bracing into smaller segments and with a combination of steel, could be made to work like trusses.

Housing: The housing could be done with Tunnel form techniques with insitu concrete, as its repetative and also its a very common technique for construction in the netherlands. (see figure above) Bowl: The stand tiers could be of precast concrete each spanning 15m, resting over the diagonal braces with a simple cleat sytem with dampeners. Roof: The roof could be could out of precast concrete as well. The radials could be continuous elements and the ring beams could semental pices fitted onto the radials with dowel bars linking them together. The erection sequence is something to research further on.

XXL_Construction and Cladding Design report Mar Munoz Catalina_sn: 4116194_group_1

Table of contents

1. Cladding concept 2. Housing cladding

2.1. Introduction 2.2. Flat part and twist: a parametric approach 2.3. Vertical housing wrapping the stadium: adaptability 2.4. North facades 2.5. South facades 2.6. Interior cladding: acoustics

3. Roof cladding

3.1. Concept 3.2. Choice of materials 3.3. Construction details

4. Previous work

Cladding concept 2scales, 2 roles, 1 concept.

“Light cladding� With the cladding we have 2 extreme scales to apprach: the large span roof construction and the tiny scale of the housing. Both will be approached with the requirements of maximum transparency since daylight is a key aspect in the whole project, both for the private functions (housing) to achieve comfort and energy saving and in the public spaces.

Housing cladding

Roof cladding

Housing clading_Introduction As a consequence of the urban analysis, we got to the main goal of our project: the integration of the stadium in the urban fabric. This integration was approached through a big urban gesture. The urban fabric would continue and twist in order to cope with the height of the stadium and therefore, build its context.

The project then moved from the idea of inhabiting a smooth stadium skin, to building the stadiums skin through the aggregation of the housing blocks, leading to a better sense of human scale in contrast with the stadium size. The materialization of this gesture is done by piling up concrete housing blocks giving a global sculptural image. The facades of these housing units become then “the skin of the skin�. The facades solution will be treated individually according to orientation and position in the wrap in order to be able to respond to different conditions.

the wrap and the bowl

This wrapping can be considered then as the stadium’s skin. Firstly, the concept of the housing was related to inhabiting the three-dimensional skin by working on the circulation, accessibility, floor space and daylight in order to achieve a wellfunctioning housing wrap. But the optimization of the housing according to the parameters of daylight and high density allowed us to be able to formally show the twist by the aggregation of housing blocks.

physical model_scale_1_1000

Despite the variety of solutions, there is a common goal: achieve comfort by getting a maximum of daylight which in such a dense fabric is one of the major challenges. Daylight is a repeated requirement in the different parts of the project, both in the housing and in the public spaces.

Housing cladding_flat part and twist_a parametric approach Housing in the flat part and the begining of the twist: An organization strategy through a parametric approach. These parts have been the biggest challenge through the combination of maximum daylight and high density. The optimization has been focused on avoiding back to back houses, getting then a maximum of surface facing an exterior space.

street view flat part

housing flat part

Because of the complexity and variety of the housing according to amount of light, size, height, orientation, size of the adyacent open spaces, back to back walls, shading from the neighbour housing blocks, etc. we considered that the design solution should also be parametric and in that sense, customized for each one of the housing units.

daylight analysis ground floor=worst case scenario

daylight analysis of the whole

Despite the desire for big windows for light catching, the different facades of a housing block will respond to the amount of light, placing bigger windows in lighter spaces. This is then related to the internal organization of the space: bigger windows for day functions such as the living room, smaller windows for spaces with less need of light or with more privacy, and no windows for the dark functions such as toilets, storage spaces‌

We did the first step, as mentioned before, optimizing the amount of daylight with a high density. Now we could use the daylight map to make the design solutions, but it would be a very rough approach which would not fulfill the previous optimization effort. Despite this last step was not yet done, it is possible to optimize the position of the openings, the size, and the functions behind these facades according to the daylight analysis. And this is the way we propose to achieve a higher comfort degree for all the inhabitants. This leads to a combination of mass (concrete) and void (glass) which responds to all the above mentioned parameters.

flat part housing

Housing cladding_vertical housing wrapping the stadium_adaptability south_wind protection

Housing in the vertical part and the end of the twist: Adaptability to different orientations These sections of the housing strip have a strong relation with the stadium bowl. This means that they only have one orientation towards direct sunlight and a second poor source of light from the cavity under the stands. This connection will be mostly used for crossed ventisouth_overheating prevention lation.

south_thermal buffer

south_fully open south_wind protection

cavity under the stands

The high density of the flat and begining of the twist part make the housing blocks protect each other, but in the vertical part, thesouth_only houses are much more exposed. sun protection We will still focus on getting a maximum of daylight through the facade facing the exterior, but with different design solutions for the north and south facades.

south_overheating prevention

In the north side, these surfaces will consist of a large glass window in the edge of the housing box to allow a maximum of light inside.

south_fully open north_maximum of light

The strategy in the south facade still focuses on getting a maximum of daylight but taking into account the different climate scenarios. We will have reconfiguration possibilites for energy saving in different climate conditions still allowing a maximum of daylight. This way we can take advantage of the direct solar radiation in winter by creating a thermal buffer (winter garden) and solve the overheating problems in the summer and by doing that, increase the visual and thermal comfort. This will be done by 3 layers: glass, sun shading and single layer ETFE.

south_only sun protection

Housing cladding_north facades

Since this orientation does not get direct solar radiation, the maximum glass surface will let as much indirect light as possible towards the interior providing the further points from the light source a reasonable daylight factor. A disadvantage of this solution is that a large percentage of glass surfaces can cause a considerable heat loss. That is why it is very important to have a low U value of the glass. This will be done by placing double glazing, being the interior pane provided with a pyrolitic coating (Low emissive glass). This way it will prevent the heat from the interior of the houses from escaping.

openable window movable aluminum frame

fixed aluminum frame

double glass balustrade (fixed window) glass (8mm) air cavity (10mm) Low-e glass (8mm)

neoprene acoustic isolator floating floor accoustic air gap insulation

steel transition profile

reinforced concrete

north facade section detail_1_10




Housing cladding_south facades Material selection: The south facade second skin does not need to be airtight or watertight. It should allow then a maximum of performance with a minimum of effort. We chose an ETFE second skin instead of a more conventional glass solution because of several aspects between which are the lightness, transparency, high light transmission and self –cleaning. Although the glass seems more transparent as a result of its crystalline molecular structure, the ETFE is still very transparent. A single layer of the foil has a transparency of 92.5 % but when the amount of layers increases, the view through starts to be blurry. This is caused by the mere overlapping of foils together with the lens reflection and refraction behavior that appears in ETFE cushions. Therefore, the most optimal ETFE solution would be the single layer according to transparency and also allowing the maximum of light transmission (94-97%), both long wave and short wave radiation, while glass only allows the short wave one. This way a decent amount of light will reach deeper into the dwellings. This choice has a disadvantage in terms of insulation. Single layer ETFE has a U value of 5.6 which compared to double glazing (2.6) or 3-layer ETFE (1.96) is considerably low. It is equivalent to a single clear glass. But this low insulation will satisfy the behavior in summer, when the buffer needs to be ventilated. Since the thermal buffer is mainly working through convection, once this second façade is opened, the ventilation removes the heat. This would have been more problematic with a glass second skin, where even if you provide ventilation, there would still be a smaller thermal buffer effect provoked by the high insulation of the glass which does not let the reflected radiation escape. Construction: A light aluminum extruded profile frame is basically needed to maintain the tension of the material, so it only needs to carry its own weight. That means that the energy needed by the users to open and close these sliding top to bottom windows is minimum and therefore, the operation is faster.

summer configuration

winter configuration

south facade

south-east facade_back opening of the housing envelope

south facade elevation

The tension of the foil is maintained by a plastic strip which is pre-stressed between the middle points of the vertical aluminum profiles of each window forming an arch shape. To avoid independent movement of the strip and the foil, the ETFE will have a pocket through which the strip will go. This double curved shape needed for the foil’s tension also helps for the behavior against wind load. Its convex shape towards the outside is the opposite to the bending moments diagram and therefore it compensates the moments. The elasticity of the material makes it deform when being exposed to wind loads, and therefore, absorbs part of the bending moment preventing from transferring it to its frame.

operability of second ETFE skin

When opening this second façade we also made use of this shape in order to protect from the wind by folding them in pairs and never having a concave surface against the wind.

south-east facade_back opening of the housing envelope



aluminum profile




preestressed plastic strip through ETFE pocket

ETFE foil

sliding glass windows with aluminum profiles

metalic balustrade

neoprene acoustic isolator separating layer ceramic floor steel transition piece

light concrete layer to achieve the inclination (1-2%)

waterproof layer drainage

0,05 0,07

drainage surface

aluminum clamp profile sliding and rotating


floating floor accoustic air gap

rail steel transition plate


1-2% inclination prefab. reinforced concrete slab



steel transition piece

blind box

connection of prefab. concrete slab to main RC structure with breakage of thermal bridge steel transition piece



strategy for cold bridge solving


1-2% inclination

south facade section detail_1_10

Housing cladding_south facades PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT plasterboard mineral fiber panel

0,05 0,3


aluminum clamp profile

preestressed transparent plastic strip

prefabricated reinforced concrete wall

steel transition piece: glued to plastic preestressed strip and screwed to profile aluminum extruded profile


tubular profile


transparent plastic strip

ETFE foil


sliding glass windows with aluminum profiles




reinforced concrete wall. Part of the stadium structure to absorb the shear stresses (every 15m)


clamp extruded profile

stainless steel hinge


south facade second skin_floor plan detail_1_5

south facade floor plan detail_1_10

Housing cladding_interior cladding_acoustics PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT Housing interior cladding strategy for sound insulation though vibrations:

Box-in-box principle


As a result of the structural concept of the project, the housing “supports” the stadium. Since both functions share a common structure, we need to achieve a sufficient sound insulation in the housing when an event is taking place in the bowl.

The internal walls of the room are installed directly onto the floating floor and supported by resilient wall ties resulting in a room which is completely decoupled from the surrounding building. This way there is a minimum risk of flanking transmission paths.

The sound propagates in two main ways: through the structure and through the wind.

The unavoidable sound transmission will happen through the structure’s vibration. To insulate the users from these vibrations we apply the box-in-box principle.

interior cladding panel

resilient wall ties floating floor neoprene strip neoprene isolators reinforced concrete structure (transfers the vibrations coming from the stadium)

aluminum L profile for the assembly of the interior walls to the floating floor.


The sound insulation for the wind can be achieved by a good choice of materials and neat construction details avoiding leaks.

suspended roof

Roof cladding_concept A light transparent raincoat. Since the cladding of the roof behaves only as a shelter, “a raincoat”, efficiency is a key aspect to take into account in such a large surface. This cladding will show a big contrast against the roof structure, the heavy concrete dome. In the end, it is a mass and void combination, a balance between the closed atmosphere desired for a football match, and the transparency to allow a maximum of daylight in the public spaces: the field, the stands and the cavity through the stand’s openings. We will use single layer ETFE foil to meet the requirements of transparency and light weight, taking advantage of the large span possibilities of the foil to reduce detailing, therefore, increase transparency, and facilitate water tightness and water evacuation. This will be done by spanning the foil along the radial concrete beams and achieving the tension needed through preestressed strips in an arch shape. The self-cleaning property of ETFE also adds to the efficiency aspect.


prestressed steel strips

tube profile 2mm

steel L profile 6mm (transition piece)

aluminum extruded profile



steel connection roof structure-cladding

Assembly process:


28 20



gutter steel plate 3mm light reinforced concrete roof structure







inner ring ETFE span










5m outer ring ETFE span


clamp piece



ETFE foil



Roof cladding_construction details

connection of steel pieces to the concrete and welding of the L profile.

500 500

Assembly of the aluminum extruded profiles by screwing to the L profiles.


typical section detail_1_5


physical model_scale _1_2

Spanning and clamping of the ETFE foil.

Assembly of steel strip by bending the edges and screwing to the aluminum profile to achieve the tension in the ETFE foil.

Roof cladding_construction details PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT D.1

ETFE single layer



radial structure every 5 m

pipe for water evacuation radial structure every 15 m

structural housing walkaround open space rain water diversion for greenery Section_1_150



Ring beam roof

Roof cladding_construction details

inner concrete ring


ETFE foil


inner concrete ring

steel connection bars

aluminum extruded profile

groove for ETFE insertion


ring gutter seam



ring gutter radial gutter

1.1m drip mold

drip mold radial reinforced concrete beam

gutter concrete beam radial reinforced concrete beam

radial section_inner ring_1_10




radial section along radial beam_inner ring1_10

Roof cladding_construction details PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT

5.5m prestressed steel strip ETFE foil

pipe for water evacuation




3m radial concrete beam integrated radial beam and vertical structural support

stands slab radial section_outer ring1_20




outer concrete ring

Previous work_other alternatives explored First approach to the skin: A smooth gesture The formal solution to achieve the goal came from an urban cladding approach following the gesture of the integration housing-stadium. The urban fabric wraps the stadium. This lead us to two main directions in the process to make a coherent design: the functional (from an organization point of view) and the visual (from the skin point of view). In respect to the skin: The skin will not only deal with the visual challenge of the gesture but also with the energetic performance.

By analyzing the site more carefully, we can see that the overheating problems in summer are not as problematic as in the more inner parts of the city. Because of being next to the water, the evaporative cooling effect takes place. During the day, the sun heats up more the land because of the lower thermal inertia in comparison to the water. Because of that, the air over the land increases its pressure which provokes a displacement of the high mass of it towards the water. The pressure difference provokes that the cooler air above the water move towards the land provoking a cooling wind which helps to reduce the temperature in the area. Because of this, it is reasonable to focus the summer behavior in the ventilation of the skin. This way, the natural ventilation of the housing could be achieved in a more direct way.

We can identify some preliminary goals or restrictions for this skin: 1) It should be understood as 1 skin wrapping the building which changes its role in relation to the housing (roof or faรงade) but always continuous. 2) A transparent skin to allow the maximum of light in the living areas. 3) The subdivision of the skin should emphasize the twisting gesture. winter performance of the skin: microclimate

The fact that this urban fabric is considered as a whole should be used in the energetic way as well. We identify the possibility of creating a microclimate under the skin. We can identify two performances of the skin according to its position in relation to the housing:

PERFORMANCE OF THE SKIN: Improving comfort and energy saving in winter, in both the urban and the building scale allowing a maximum of light through it.

1) The horizontal one serving as roof of the low-rise neighborhood. Improving social relations in the outdoor space by creating a more comfortable atmosphere, a microclimate. 2) The vertical one serving as the second faรงade of the housing. Both deal with sustainability from the thermal comfort point of view. To determine in which way the skin deal with the comfort and energy saving we identified two main paths: 1) Using the second skin behavior in winter and summer 2) Focusing on one specific problem: winter The first option requires a lot of adaptation. When having a transparent second faรงade, winter comfort can be quite achievable but we have an overheating problem in summer. This problem can be solved through shading the second skin and ventilating the cavity. In this case, the double faรงade would also be energy efficient in summer but paying a price for it, the transparency. It is important therefore to evaluate the need of the second faรงade in each situation.

summer performance of the skin: ventilation

ADAPTIVE SYSTEM: Focused on the opening of this skin for maximum ventilation.

Previous work_other alternatives explored Possibilities of the subdivision of the surface:

We can see that the division of the surface in one direction or the other has a lot of influence for the emphasis of the twist. In the first two examples we can understand the subdivisions as the lines being the generators of the twist emphasizing the gesture. The perception of the twist increases proportionally to the number of lines.

Possible solution: Transparent strips which can rotate independently achieving an adaptive ventilation. In the image the possible horizontal display is shown.

Problems of this solution: - The scale of the project_ Too many partitions to assemble, operate, maintain... - Loss of transparency because of the needed frames to make the envelope waterproof (at least in the horizontal display). - A too big effort for what is achieved. Main entrance to the stadium_a roof becoming facade

We will then try to reach, with the same concept, a more feasible solution.

Previous work_other alternatives explored Second approach to the skin: large span transparent strips

Taking advantage of the high transparency of ETFE foil, its lightness and its large span possibilities we evaluated the option of making strips from top to bottom of the facade with the possibility of rotation around one axis in order to achieve the ventilation of the cavity required in summer. We reestricted this second skin to the behavior of second facade, discarting the roof mentioned before. The roof would be a big investment with a quite narrow performance at the same time as it conditions the whole skin materialization to achieve watertightness. We decided to apply the second skin performance tothe vertrical part and gradually make it dissappear along the twist till there is no skin in the flat part.

Problems: - Too large surfaces, specially for having a dynamic system. - Possible conflicts between the different desires of the users. - The strips which gradually disappear in the twist have a mere aesthetic role. The next step will be focused on the subdivision of this large strips into smaller pieces, easier to operate, and becoming gradually smaller pieces which will end up being individual housing second facades. Third approach to the skin: subdivision of the strips

Educated randomness: subdivision of the vertical strips leaving openings in the walkarounds of the stadium.

from the individual to the system

This way of building the skin would go from the individual skin of an individual housing block to the build up of a system, taking the advantages that a larger buffer zone has. From a sustainable point of view this is a positive approach in terms of energy saving by making the different housing units cooperate for a global thermal performance. Despite this, there is always the question of wether each user should be able to regulate his own climate. As can be seen in the final project, the final design solution of the skin focuses on the individual housing performances. In this specific project, that solution ended up fitting the concept best, keeping the strong image of concrete boxex, but an approach such as the one just proposed could have also made sense in terms of sustainability.

References: Unilever head office (Hamburg)

from the individual to the system

Previous work_other alternatives explored

exterior continuous second skin_facade section south facade section_1_20

Previous work_other alternatives explored 2,5



At this point there was a shift in the role of the cladding, we finally decided to give priority to the image of concrete boxes, and therefore, the housing second skin would be fragmentated and introduced in the concrete “frames� of the housing blocks. In the following page the direct translation was done: taking the detached skin solution and pushing it towards the inside. In the final solution, the reduced scale of the intervention allowed to refine the detailing and achieve a more elegant and lighter design.

exterior continuous second skin_floor plan

south facade floor plan_1_20

zoom in floor plan

2,5 detail_south facade floor plan_1_20

Previous work_other alternatives explored

planta south facade_1_20 second facade inside housing unit_section

section south facade_1_5 section detail

elevationunit_elevation south facade_1_20 second facade inside housing

plan south facade_1_20 second facade in floor housing unit_floor plan

Previous work_other alternatives explored ETFE shorter spans: ROOF CLADDING_ETFE In the roof, we considered the option of applying individual cladding units in each one of the gaps that the concrete leaves. But this would lead to too much unnecessary detailing and the need of gutters in both the radial and the ring directions. We therefore decided to take advantage of the large span possibilities of the ETFE foil and have single radial ETFE elements supported on two consecutive radial beams.


ETFE foil

folding and welding of ETFE

steel tube to tense ETFE edges steel plate/ water evacuation/ connection to cladding structure by welding

cross section_1_50

cement connection pieces reinforced concrete

cross section_1_10

steel arches to tense the foil

longitudinal section_1_50

longitudinal section_1_10

Sustainability A sustainable approach:

THE CAVITY_Daylight optimization and analysis:

A combination of scales by integrating social housing and a stadium within a public space searching for a two-way benefit keeping the area alive 24/7. This is our main goal: social sustainability. To make this succeed we worked on several aspects.

Further detailing about this process can be found in the individual report of the Digital Design Manager.

Daylight analysis in the cavity

Integration through human scale.

housing flat part

cavity under the stands

Ventilation: The housing wrap around the bowl leaves a cavity underneath the stands which we decided to use as a continuous public space. Despite the daylight has been improved to reach fair enough levels, the cavity remains protected from solar radiation which makes it a cooler space.

street view flat part

We understood the area, punctually occupied by the pitch, as a public sports field, keeping this way its original function and allowing kids to play in their team´s stadium. A continuous public space from the front square and along the cavity under the stands is created facilitating the permeability and the maximum use of the space. For the quality of this cavity it was important to increase the amount of daylight which was done by removing housing units from the housing strip, creating openings in the stands and removing the first tier of stands creating the main light source.

This is especially relevant in summer when the air from the cavity can be used for natural ventilation of the housing units. This air would be cooler than in the exterior facade of the housing which would provoke an air flow from the cavity, outwards. By using this principle, we provide the housing with the most optimal natural ventilation, decreasing the cooling load need. It is an ideal summer natural cross ventilation. section through stand’s openings

Sustainability south_thermal buffer

THE HOUSING_Daylight optimization and analysis:


south_thermal buffer

The high density of the flat and begining of the twist part make the housing blocks protect each other, but in the vertical part, the houses are much more exposed. We will still focus on getting a maximum of daylight through the facade facing the exterior, but with different design solutions for the north and south facades. south_wind protection In the north side, these surfaces will consist of a large glass window in the edge south_wind of the housprotection ing box to allow a maximum of light inside. The strategy in the south facade still focuses on getting a maximum of daylight but taking into account the different climate scenarios. We will have reconfiguration possibilites for ensouth_overheating prevention ergy saving in different climate conditions still allowing a maximum of daylight. This way we can take advantage of the direct solar radiation in winter by creating a thersouth_overheating south_thermal buffer mal buffer (winter garden) and solve the overheating problems in the summer and byprevention doing that, increase the visual and thermal comfort. This will be done by 3 layers: glass, sun shading and single layer ETFE. Further detailing about this process can be found in the individual report of Cladding and south_fully open Construction. Daylight and density optimization and daylight analysis.

south_wind protection

Vertical housing: 1 facade facing the exterior and the other facing the cavity

south_fully open

south_only sun protection

At the level of the housing units, our aim was to achieve maximum visual and thermal comfort through the search for a maximum of daylight with a high density, combined with the adaptation of the specific facades to different orientations. The further development of this concepts can be found both in the Architecture individual report and the Cladding and Construccion report.

south_thermal buffer

south_overheating prevention

south_wind protection

south_fully open

north_maximum of light

north_maximum of light

Because of the high complexity and variety of the housing according to amount of light, size, height, orientation, size of the adyacent open spaces, back to back walls, shading from the neighbour housing blocks, etc. we considered that the design solution should also be parametric and in that sense, customized for each one of the housing units. This means that the position and size of the windows and therefore, the corresponding interior functions would be parametrically related to the daylight analysis of the figures above. In this case, the daylight map has been used to placed the windows accordingly, but the aim would be to have a parametric approach for that and therefore take full advantage of the optimization in order to achieve a higher comfort degree for all the inhabitants.

south_only sun protection

south_overheating prevention summer configuration

south_only sun protection

winter configuration south_fully open

north_maximum of light

Adaptability STADIUM + COMMUNITY We designed the stadium as an urban area, adapted to the context. In order to make use of such an investment and as an answer to the urban area, we introduced housing and public space as two of the main driving parameters in the design process having a social approach. Designing from the context to the bowl core and not the other way around which is commonly seen in the design of stadiums. Here, adaptability does not occur by having a transformable object but by the coexistence of the two functions both in time and in space. Like the two sides of a coin.

Adaptability through reconfigurability: Reconfigurable stands: This solution came as an initial demand from the public space scenario (no match). Our design goal was to increase the physical and visual permeability of the space in terms of accessibility and quality of the space (daylight in the cavity). In our first approachs we thought that a good solution would be to remove the first five metres of stands in order to create this effect, but this would suppose a compromise with the match scenario. We finally got to a solution which fits our requirements for the improvement of the public space, at the same time as it adds an extra value also to the match scenario. This solution consists of reconfigurable stands which satisfy the needed stands for a match and the need of light in the cavity by lowering them. This reconfiguration is possible through different blocks, for people to stand on, with variable height by using air pressure. Once the two main scenarios are satistied we decided to give this solution an added value by creating different configurations for the no-match scenarios.

At a first glanze these functions might look incompatible but our aim was to adapt the project so that each one of them is an added value to the other. We can say that the project is community+stadium and not community or stadium, in other words, simultaneous scenarios. The dwellings and the stadium were developed paralelly and interconnected. Dependant on each other. This way, we would make the best and maximum use of such a construction. Having a continuous function (housing) and being able to absorb the peaks when a match is happening, is the challenge that we have taken. We can identify a “core� for each one of the functions. For the housing would be the housing strip and for the stadium, the bowl. But there is always one function that dominates. To be able to optimize the ruling scenario in each case, we focused on a second degree of adaptability. Adaptability through reconfiguration. As it can be seen, adaptability has been a present parameter throughout the entire design strategy. Both in the large scale (structure, circulation...) which is further developed in the Structural designer report and the Architect´s report, and the small scale, for instance, the adaptability of different facades to amount of daylight or to different orientations for a more sustainable approach. More information to be found in the Cladding and Construction report.

standing stands

street furniture

sitting stands


removing stands for vehicles when needed (example: concert)


Sliding pitch: The system would be materialized by using airbags combined with a scissors lift system. We chose for an air pressure system in order to have a fast responsive reaction of the stands to the users and therefore be an “atraction” specially thinking of the football matches crowd. The first rows in the stadium are usually the most active ones, as we could see when we went to a football match of Feyenoord. Therefore, these responsive standing stands could be a success in these locations participating in keeping up the atmosphere in a game.

After these first reconfiguration possibilities for the match-no match scenarios, the field area will be accessible when there is not a match going on so that kids can play their own football matches there. But this is again in conflict with the idea of an “optimal” football field for Feyenoord, since it is very hard to keep the grass in good conditions, and impossible if the field is accessible daily unless we would decide to use artificial grass. We considered the artificial grass option, which is also allowed in the FIFA requirements, but we finally dropped it. A football stadium should have the field that their team wants, and it is not likely that artificial grass would be accepted. It is something that could be argued though, but at this stage of the design should be questioned since the wrong solution can ruin the whole public space concept (if in the last moment they require real gras) or create an unwanted stadium because of the artificial grass. We decided not to make a concession in favour of the public space, but instead, fulfill the requirements for both scenarios. This would be done by sliding the pitch out of the stadium in the east part. We though that the investment in this solution is worth it making sure that the concept is fulfilled.

Structural solution for the east side structure in order to allow the sliding of the pitch

Air bags

Air bag scissors lift retractable stands

The housing as a high beam on the east for achieving free span

XXL, Stadium de Kuip, Rotterdam