FEM Analysis...

AKT has run an initial FEM analysis on the roof structure, and well...we've got a bit of work to do.
Though significantly lighter than conventional concrete, the Fibre-C is still concrete, and the self-load of the material is a bit more than our geoemtry can handle at the moment. Basically, with the tilt/lean of the roof structure, the self-load of the structural material, and the non-continouous nature of the structure....our notch joints are taking a hell of a load. The moment forces that these joints are taking is very high. We are also experiencing high stresses and deformation in the profiles due to bending in their weak axis. AKT has told us we need to reduce the stresses by a factor of about 6 (no kidding...my stress factor has got to be +100 these days).

We've got a few options for reducing these stresses, but it looks like it's going to be a combination of them all:

1. Decrease the tilt angle of the roof structure. By reducing the angle by 15 degrees we gain a factor of 2. We also lose some of the dynamic formal movement and drama of the structure.

2. Introduce bracing, especially at the sides of the pavilion. This could be done by infilling flat sheets of fibre-c stiffeners between profiles at various locations. This could also detract from the visual and structural purity of the pavilion.

3. Add more primary ribs at the side faces. This might alter the visual effect of the moire pattern, but could also be interesting if done as a gradient of spacing. I also find it interesting to architecturally express where the structure is performing the most.

4. Increase thickness of material at primary ribs to 13mm, and decrease thickness of material at secondary profiles to 10mm (reducing the self-load).

As I said, we've got some work to do. All of these decisions need to be looked at before we can make a call on them. We need to maintain our design concept, while finding a structural solution that suits. But in particular...we need to so so ASAP!

Here's a look at the revised wire model with spliced profiles and intersection nodes we sent over to AKT today for a quick analysis. In this version, we have reduced the tilt angle by 10 degrees on the front face, and 5 degress on the back.
On another note, once again we have also revised the bench geometry again. Don't worry, it won't be the last time. As you can see below, we are using the 3.6m x 1.2m standard sheet size of Fibre-C as the module for sizing our profiles.
In light of this, we have now lowered the height of the seatback/counter, so that it drops within the 1.2m width of the sheet material. this allows us to cut the entire bench profile in the primary direction, in one continous piece. this is a very minor change, but one which saves us huge amounts of hassle and detailing.

joint details

We've made some progress on the joint detials over the last week. The two models we were looking at use silicone gaskets to provide a cushion between the interlocking profiles and here are the two mock-ups back from the RP lab. Thanks to Jeroen for all his help.

After a design team meeting, we've decided to go with the second option because it can deal with a variation in angles in two planes; it acts as a rotational stiffener once in place, and it will provide a locking resistance against vertical shear.

The assembly process has been reduced to a minimum - a pair of gaskets will be bonded to the notches on the primary concrete profile in advance. On site, the cross profile will be inserted and then the remaining pair of gaskets can be mechanically fixed with one pin each to lock the joint together.

bench in progress...

more revisions to the bench profiles. the original competition entry had the profiles revolving with the geometry of the bench, however this poses problems with how we slot the bench profiles with the deck underneath. now, we are continuing the primary profiles of the roof and floor into the bench. for the cross-members we are looking at taking the sections in one direction for the vertical surfaces of the bench (horizontal sections) and another for the horizontal (seating) surfaces of the bench. we still need to work on the density and spacing of the profiles, but i think we now have the principle in place.

as the deadline approaches and the complexity of joints is exposed, we are basing many decisions on the infamous "KISS Principle".

however, as usual, all sections are completely planar, but never parrallel...

more from theverymany...

here's a few more images from Marc Fornes of theverymany, and his entry into the DRL10 pavilion competition. Marc is doing some fascinating generative geometries in RhinoScript. This entry explores the use of a Danzer Tile, which is an aperiodic tiling system. Check out his site for more. As seen in previous posts, Marc has generously been supplying us with coding support to help us automate the process of producing the documentation for our pavilion.

more joint options

work in progress...

the bench profiles are slowly beginning to take shape....here are some screen shots from today's progress...

moving towards mock-ups...

A few options on joint details. We have a range of 30° on the angle of intersection for each joint. We are proposing that there are then 6 details, each of which can acommodate a variation of 5°. Rieder is confident that their material is strong enough, and their fabrication process acurate enough, that we could do a concrete on concrete joint, with no gaskets or fixings. AKT is not confident about this approach. Not only do they want the gasket, but they also want a mechanical or adhesive fixing. Above is a range of options showing a range of 6 variations each on a gasket-less variable notch detail, and two rubber gasket details.

AKT is also proposing a series of details, which we will post later.

All of the details will be tested through AKT.

In parrallel, we are producing a 1:1 scale plywood mock-up to test fitting and assembly. Here's some images of the 3D model of this mock-up. Yosuke will be coordinating a team of the current DRL phase one students to fabricate and assemble this mock up.


Once again, special thanks to Marc Fornes of theverymany for his assistance with providing the Rhino scripting tools to notch and unroll these surfaces!!

the 58 unrolled profiles for the mock up, notched and ready to be cut...

a few words from our sponsor...

Yesterday afternoon we had a meeting at the offices of Zaha Hadid Architects (pavilion sponsor), with event organizers Patrik Schumacher (ZHA/AADRL) & Yosuke Obuchi (AADRL), structural engineers Hanif Kara, Oliver Bruckermann, & Jugatx Ansotegui (AKT), & our material sponsor Wolfgang Rieder (Rieder Co.).

We learned quite alot from Wolfgang regarding the possiblities of Fibre-C as a material, and he has generously committed his staff to helping us develop the design. The enthusiasm and insight of everyone involved has been fantastic.

We wiill post more results from the meeting soon, as we will be producing a series of 1:1 mockups of joint options for structural testing (AKT), a 1:1 plywood mock-up to test fitting of panels (AADRL), and a 1:1 Fibre-C mockup for fitting and assembly tests (Rieder Co.).

In the meantime here's some info and images documenting the process of fabrication for Fibre-C panels, sent over this morning by Maria at Rieder.

" fibreC, which is also known as “concrete skin” and has won international architectural awards - is a concrete panel reinforced with glass- fibres which combines the advantages of concrete and glassfibres in one product: it is as solid, moldable and durable as concrete, but thanks to the glassfibres also thin-walled, fireproof and light-weight. Like a skin of concrete, it allows the construction of slim elements with a tensile strength. The extremely thin concrete slabs contribute to the new language of shapes."

"The high consistence of fibreC results from the reinforced glassfibres."

"A special extrusion process incorporates layers of glassfibre into a concrete matrix; in the top layer and underlayer the fibres are undirected and scattered, in the medium layer they take the form of roofings (fibre bundles). The omission of steel reinforcement allows the construction of “slim” concrete elements which are highly stressable despite being extremely thin-walled. The result is an extremely thin slab with 0.31“ to 0.39“ thickness, which is very light-weight, yet has a high flexural strength. The slabs can be dyed in different colors before being hardened for 28 days."

"By using genuine natural stone with iron-oxide pigments, our products resemble natural colors to the smallest detail; the result is “technological marble“ without coating. The process using iron oxide pigments fulfills our sustainability requirement. The authentic colors of concrete skin blend perfectly into the existing landscape and communicate with nature and the environment. One of the most fascinating colors is “liquide black“, a deep rich black produced with unique copper stone, where genuine oxidized copper dots sometimes gleam through the surface."

Profiles will be cut by CNC water-jet machines from standard 3.6m x 1.2m fibre-C panels.

We have also gone ahead and specified a color for our sheets...we are using the Ivory color with a Ferro (sanblasted) finish, as highlighted above. We wanted to use the rough finish as it truly expresses itself as concrete. The rough finish will also help us by providing friction at the joints. The polished finish is really nice, but comes across as a solid surface application (i.e. corian). There will be slight variations in the colors of individual panels as they all cure differently:

"Vivid structures with an interplay of changing color shades and somecloud effects, rather than dead and clinical surfaces, are characteristicof fibreC. Differences attract and are understood as what they are– a typical characteristic of a natural building material."

crease angle plug-in for rhino...

here's some screenshots from today's progress....

we have begun laying out the standard 3.6m x 1.2m fibre-c sheets against our geometry. the lenght of each section is determined by this sheet size. at the moment, we are going with the 3.6m length, as it makes for a lighter element that can be handled by hand. however, AKT is suggesting that we move to the 5m sheet...that means we would require a crane for assembly, as the weight of each individual profile would be over 25kg, which is the legal limit in the UK for builders to lift by hand...BUT it offers greater structural optimization as we would greatly reduce the number of splices required in joining discontinuous members....
we have also created an intersection network for AKT to analyze, as well as documenting all of the angles of intersection for all of the planes (thanks to the crease angle plugin for Rhino). as you can see below, no two angles are the same...although many are within very close range to one another.


we'll have more on some ideas regarding how we can deal with these angle variations soon...AKT has a few options they would like to explore, and we are developing a couple as well...

another DRL10 pavilion...

this one from Alvin Triestanto...