Formwork tectonics - to round a square column

[2-meter high fabric-formed concrete column]

Formal consequence

The use of flexible molds entails a direct formal relation between the tectonic principles of the formwork structure, the type of concrete pour, and its concrete consequence, so to speak. It is a potential to develop the details in formwork construction because they are technical as well as aesthetic/form giving. On the other hand, this formal consequence means that all mistakes show themselves as well with equal power, and this is a disadvantage of the building method unless you see mess-ups as a charm. The dilemma of course is that working meticulously in construction shows high-level craftsmanship. This comes at a price in hours and wages, in Denmark 70% of the cost of concrete elements go to wages.

[Images of fabric-formed plaster model 1:4] 

Formwork tectonics

One of the student groups at the 2013 TEK1 workshop at RDAFA also concluded this from their preliminary experiments with fabric formed plaster casts. When attempting to literately tailor the fabric formwork the ruthless character of the poured plaster changed initial intentions to less controlled and little desired folds and bulges (not shown here). It took a long time to work with intricate principles and it still proved difficult to anticipate and achieve the results they desired. As a result, the students devised a formwork principle that, while simple to construct, would still result in sharp, controlled edges as well as soft curving surfaces. The principle was tested in the model shown above

  

Formgiver and structure

The storyboard shows the steps of constructing the column and the simplicity and tectonics of the structural formwork principle. The title is Compression and Expansion and refers to the role of the formwork sheets and the consequence on the poured fabric mold. I love how the interlocking and formgiving mdf-sheets are also what holds up the fabric tube. The principle means that the column has a square footprint and always two flat surfaces and two curved ones, i.e. quite a complex geometry.

 

[Left: the formwork structure ready for the pour. Right, detail of the formwork structure before stripping ; bits of cement has filtered through the fabric along with excess mix water during the pour.]

[Sketches from student report showing the principles and the steps of constructing the formwork]

 

Creases and shifts

Despite their work at simplifying the process for ultimate control, for the resulting fabric-formed concrete column, students were unhappy about little creases from the fabric as well as the asymmetry of the bulges. Especially the bottom has uneven bulges, which could have been avoided by adjusting the fabric tube before and during the pour, as well as working the concrete from outside the formwork – simply moving the fresh concrete by pushing against the membrane mold. Note, however, how identical creases can be found on the surface of the plaster model cast using the same principle.

This first meeting with concrete and principles formwork tectonics for first-year students is promising. If you are in Copenhagen, swing by the quay behind the RDAFA and check out the columns.

Credits

Work and drawings by: Oskar Mannov, Sidsel Petersen, Nora Ødegård, Cuong Tran, and Toke Ridderson.

TEK1 2013 concrete workshop organized and taught by Finn Bach, Tenna Beck, and Anne-Mette Manelius (yours Concretely) for the Institute of Architectural Technology at the RDAFASA

PS

I have written much more about formwork tectonics and stereogeneity (concrete as material and as process) in my PhD dissertation

898 - Fabric-formed concrete couch

Inspired by the previous post about Nacho Carbonell's soft concrete, here's a few images from my own backyard.

898 (kg)

Carbonell's 'soft sofa' reminded me of something that I haven't shared with you - so here's another one - a couch cast by my students during a TEK1 workshop in 2011. The focus in the workshop was on exploiting sharp edges and curved surfaces. The theme was benches but this piece is more of a couch-thing than a bench.

The 898 is cast in fabric-formed concrete. The edges of the furniture is controlled and cut out of rigid plywood. Its surface, on the other hand, is made to appear soft and cast in fabric restrained with a garden fence netting.

[898, couch. From TEK1 concrete workshop at the Royal DK Academy, School of Architecture]

The title of the piece, 898, refers to its calculated weight... The really attentive Concretely reade, may recognize the surface. The students who made the 898 were inspired by the expression of an earlier fabric-formed piece for which the forming method was also its expression.

[Fabric formed concrete surface from 'Wall de Mort'. I discuss the project in my PhD dissertation - and regret to admit that I changed its funky title to the Net Wall... ]

898 couch by:  Cisse Bomholt, Philip Messmann, Michael Sivertsen, Maja Kozak Dehlin, Amanda Lilholt, Mathias Rasmussen, Søren Rosendahl Svare and Kenni Bruun Rasmussen.

Wall de Mort by: Siri Reisæter Rasmussen, Astrid Asmussen, Rasmus Gosvig, Christian Bencke Nielsen

TEK1 teachers, 2011: Anne-Mette Manelius, Finn Bach, and Johannes Rauff Greisen

Workshop - Draped Concrete in the Rotation Column

This Rotated Column was designed by students and constructed during the last weeks' TEK1 workshop at the Royal Danish Academy of Fine Arts, School of Architecture

[Rotated fabric-formed concrete column]

 It is easy to see the principle behind Rotation Column: the formwork tube is rotated to create a spiral shaped column. The top and bottom are rigid boxes to supply contrast.

The formwork membrane is attached to the top and bottom and furthermore zip-tied to the reinforcement inside.

[Detail of the formwork before the pour. The series of wires is actually a very simple and strong way to make a seam in fabric formwork. The to ends are rolled up and pinched with twisted metal wire or zip-ties]

 While the team had already tested the principle in several plaster casts where the fabric got stuck in the plaster, they kept this principles and optimistically hoped that the concrete would not react the same way at the large scale.

The team had to use a heat gun to strike the formwork stuck in the concrete. At the end a wonderfully soft-looking column came out.

The Rotation Column (Draped Concrete) was part of the TEK1-concrete workshop in 2013.
Members of the Team: Alexander Egebjerg, Aron Wigh, Markus Nilssen Kinstad, Albin Arvidsson, Lea Møller, Dahlia Dudas
Supervisors: yours concretely, Finn Bach and Tenna Beck

Fabric-Formed Concrete Columns

Just finished a wonderful workshop with first-year architecture students at the Royal Danish Academy of Fine Arts in Copenhagen. The theme of the workshop was columns.
In the past four years I have organized and taught a number of similar full-scale workshops but never written much about the workshop frame. This post will go through some of the thoughts behind the elements and activities of the workshop.

[The family of fabric-formed concrete columns]

[The formwork structures on pour day with the concrete pump in the background]

Studying concrete in relation to its mold
Concrete is studied best in relation to its formwork, as material and process. The use of fabric formwork is an excellent tool to introduce concrete and formwork principles in order to enforce an individual and curious understanding of what concrete and the process of casting is all about.

The concrete workshop is a highlight of the TEK1 course, a mandatory four-week course about architectural technology. This year, 35 students (a quarter of the class) were in my workshop. 

Columns

The theme of the workshop was columns. As the most basic structural and architectural element the column is loadbearing as well as the defining space. The student's approach varied greatly. And their focus sprung from either the textile principles of draping or sewing, or principles of the construction process and how to use minimal means and simple process to construct their formwork.

For a fabric-formed column the main objectives of the formwork is a) contain concrete, b) stay in place (erect), c) additional sculptural features. A and B remain the crucial aspects but the point is, of course, that by erecting the formwork structures in a clever way, the formwork-tectonic principles also have a direct formal consequence on the concrete column. Furthermore, the closing detail or seam of the fabric is important as well. Basically, focus remains on a few important details and their effect - as ornament or as 'invisible'

Afternoon 1: Brainstorm

First step in our workshop is a one-hour brainstorm. At this workshop, 6 groups sketched and played with fabric for an hour after which we have a short pin-up. The point is that by sharing these initial ideas creates a pool of knowledge as well as a number of themes and categories to discuss. Themes of concrete's sculptural form, textile notions, and design principles derived from construction become clear from discussing the sketches and ideas. Looking back now it seems that this initial categorization of approaches has helped the teams to remain clear - at least the themes are pretty clear in their work, anyway.

Afternoon 2: Plaster

The workshop is all much about making. And about making something fast. 

A great way to make decisions and learn from principles in fabric formwork, is to do small scale casts in plaster. This is a method practiced at CAST and it works really well in the student workshops. For this workshop we had a plaster lab allowing us to mess around with plaster and the student teams were super enthusiastic, playful and productive.

[Detail of plaster cast in a fabric mold with impactos]

[learning by doing, casting plaster in fabric molds. The blow-out experiences are much nicer to experience first at a smaller scale]

[Selection of plaster models cast in a few hours]

Day 4: First Concrete mix and pour

As a way to change scale and focus from plaster to concrete, it was fun and appropriate to build simple formwork frames as well as mixing and placing concrete, heavy as it is. Each team had their plinth and were given U profile reinforcement to place according to their column design.

It turned out excellent to leave the formwork boards on the foundation during the entire workshop. In this way the column formworks could be fastened to the ground. 

[Students placing concrete mixed in the mixer in the background. The wooden formwork boards allowed the teams to attach their formwork bracing]

Constructing full-scale formwork structures

Producing several plaster casts allows teams to discuss construction techniques as well as the expression and geometry of their finished column. The full-scale work entails a different and much more material oriented approach. One team wanted to stitch their formwork together and had to devise a special needle tool to do it at this large scale, with a thick nylon rope, and in a controlled manner.

[Student group discussing their principle of stitching as an element of formal and technical form tie or restraining]

[The stitched formwork. The column becomes more like a wall or at least a double column]

[Over the top but great. Our 2 cubic meters of concrete came with a pump as well as a truck. The 'pump man' was the coolest and a very patient guy]

[Concrete fever - Keeping cool and waiting for concrete]

[The rope remains embedded in the concrete. The team managed to remove the fabric around the stitches]

Acknowledgements

The concrete factory Unicon sponsored the concrete pour

We received cement from Aalborg Portland to mix and pour the foundations

Supervisers and organizers: Anne-Mette Manelius (yours concretely), Finn Bach and Tenna Beck.

Stitched Column (Betonsyning) team: Agnes Garnow, Marcus Innvær, Mikkel Kühnel Witthøfft, Alexander Kristensen, Rasmus Feddersen, Michael Brandrup 

Formwork tectonics

In a series of photographs, my friend Signe Ulfeldt has documented formwork-tectonic details right after a concrete pour. Her photos lifts the introductory chapters of my dissertation - but why not share the niceness with the readers of Concretely.

[Image of newly poured fabric formed concrete at TEK1 2011. Photo: Signe Ulfeldt]

For fabric formwork there is a direct relation between formwork design and concrete form and surface. The role of the construction of formwork structures thus acquire careful attention to all details. Yet, the aesthetics of formwork structures while performing its duty supporting concrete is left only as traces or more directly as impactos on the cured concrete structure after the formwork has been removed.

[Images of newly poured fabric formed concrete at TEK1 2011. Photo: Signe Ulfeldt]

Photographic attention

Signe assisted in the making of Composite Column in 2010. In 2011, the last concrete workshop I organized and taught before writing up my doctoral dissertation, and which I will defend two weeks from today...,  Signe exchanged her physical assistance with that of the observer. She focused her photographic attention on the relation between formwork structures and the freshly placed concrete in a series of photographs that I just love. The materials and rhythm of the formwork structures are captured to form graphical patterns of their own. The concrete is still fresh and the fabric is 'sweating' excess mix water. Yet only the image of a masonry tool, above, and the home made 'sewing aggregates', below, refer to the recent presence of the workshop participants and a massive concrete truck.

[Images of newly poured fabric formed concrete at TEK1 2011. Photo: Signe Ulfeldt]

[Images of newly poured fabric formed concrete at TEK1 2011. Photo: Signe Ulfeldt]

Benches on the Quay

The attentive fabric-former may wonder about the extensive presence of timber in the images. Well, the TEK1 2011 was all about benches and the focus upon the use of fabrics as formwork turned out the receive a smaller role than most student groups' desire to design, the assignment for the workshop was a bench for the quay behind the studios of the Royal Danish Academy of Fine Arts, School of Architecture. (RDAFASA). You can still come around and enjoy the afternoon sun sitting on some of the results.

Thanks again Signe for the nice work -

Concrete Benches cast in fabric

Wow, what a while it's been since my last post - well, as for now I've just finished a great workshop with 80 (yes, 80) first year students of architecture and architectural engineering. In a week's time the students had to design and produce a concrete bench: This included designing the formwork principles and building the formwork. Finally the students had to pour the pieces of around 300 liters each (750 kgs of concrete), and finally - strip the formwork and reveal the concrete evidence of the experiments...

[Students pouring the fabric formed concrete bench - and getting advice from the concrete sponsor, Unicon]

Here's an older post with some images of references to benches.

No blow outs
The pieces of this year's workshop weren't super tall - the tallest formwork was 140 cm high. Out of 12 pieces and 4 cubic meters of concrete, we had no blow outs - yipee - this wasn't really the case last year. Formwork pieces were all 2 meters high - and only one student piece survived in its initial state... read more about last years workshop here.

The Clover
Below are some images of the Clover Bench. More info to follow. Enjoy!

['Trekløver', the Clover. Fabric formed concrete bench. Student work at TEK1]

Do I need to say that the focus was on fabric formwork?

Besides being the subject of my research, fabric formwork has great potentials for introducing concrete to students of mostly no previous experience to either pouring or building formwork - in fact building anything yet :)

Formwork tectonics

First of all, building with light weight fabric lets you produce quite large structures just because the weight of the formwork structure is kept down.

More importantly (says the teacher) there's a structural hierarchy in building fabric formwork - an apparent material dialogue to be considered. The material dialogue is between the concrete and the three elements that the formwork is made out of: the frame holding the fabric, the fabric itself, and a restraining method to keep the fabric in tension and control bulges during the pour. 

Formal consequence

When the concrete is poured as an almost ruthless matter the formwork is really put to the test. All choices made during the construction of the formwork results in a direct formal consequence on the form and surface of the concrete.

[Fabric form for the 'Clover' - without the inner form, Student work]

Formwork statics is quite an interesting subject - designing formwork structures the students get a grasp of pure tectonics. Quite simple structural principles may result in striking concrete forms :)

[The funky inner form for the Clover. Students used scrap vinyl flooring to create a smooth surface inside the bench. Student work]

Credits to the members of the Clover team who built the formwork shown above: Alva Altgård, Symra Joner Andbo, Helga Hallgrimsdottir, Rasmus von Wurstemberger Nielsen, Marie Rugholm Nielsen, Andreas Klestrup Hansen. Students study at RDAFA or DTU

The workshop was part of a course held by the Institute of Technology and co-teachers were Johannes Rauff Greisen and Finn Bach

Lecturing at the Danish Architecture Centre

If you're in Copenhagen, do come by the Danish Architecture Centre next Wednesday Dec 8th, 2010.

Along with two great speakers I've been invited to talk about building materials of the future - which of course in my case would be fabric formwork.

[Detail from fabric formed concrete chair - the Ambiguous Chair]

The talks are in Danish, I'm afraid - but feature three different approaches to working with material futures - besides my own which is the low tech approach yet new combination of materials known for millennia, two other architects are these:

Mette Ramsgaard Thomsen who was just appointed Professor at the RDAFA, is the head of CITA and a leading figure in the practice lead discourse of digital practice.

Kasper Guldager Jørgensen is head of development at Danish Architecture studio 3XN. He's really into features of emerging material technologies and how to embed them in the architectural practice of the firm.

Composite columns or bastard formwork

While teaching last week’s crazy student workshop I had the chance to test a principle as part of a series of investigations on what I call composite - or bastard formwork... The idea is that combining fabric with materials of other properties offers perspectives regarding concrete form, surface and production.

The fabric is used as the constraining system and the piece I made is a 2m high set of columns
An aim of the experiment was to use a minimum of materials which doesn't explicity add formal or surface qualities to the concrete structure.

[Yours truly, Anne-Mette Manelius proudly posing with the bastard formwork after the pour. Photo: Mette Madsen/Pihl]

[Yours truly working at stripping the formwork - everything didn't go all easy-peasy. Photo: Signe Ulfeldt]

 [My lovely assistant, Signe and I with the piece - a very little fellow next to the student works - but he's mine]

One of my favorites among the student works is this lovely piece - the students call it Wall de Mort - haha.

Wall de Mort - or the amazing concrete quilt

 [Image: Concrete surface cast in fabric formwork braced in a cheap garden fence. Student work. Photo: A-M Manelius]

A wonderful concrete piece was stripped just before I went home after yet an intense workshop pour day described in the previous post. The students called it Wall de Mort in their report - I wonder if they had a tough time?

The plastic, shiny surface really cheats the eye - both on camera and on site the concrete surface really doesn't look like concrete but as if the fabric is still there.
Here are a few shots from the piece cast in fabric and braced by a cheap garden fence. The formwork system is so simple that it deserves publishing -

[Detail of formwork before the pour]

[Image of students during the pour - Rasmus uses a shovel to compact the concrete from the outside. Photos from the workshop]

 [Image: The fabric formwork bulging after the pour. Photo: Tenna Beck]

It's truly fantastic that such little use of material can produce a structure like this!!
To keep the form from bulging out the constraining fence on each side of the form was tied together with metal wire in a system of carefully placed ties. A simple variation created a really cool pattern on the surface of the concrete.

 [Image: The fabric formwork and bracing fence. The pattern comes from excess water/cement paste gone through the woven fabric during the pour]

[Students working on the stripped fabric formed concrete. Photo: A-M Manelius]

[Image of fabric formed concrete slab. Rasmus removing metal wire which held the form together. Imprints from garden fence. Photo: A-M Manelius]

[Little streams of cement paste found their way through the fabric landscape sandwiched between two pieces of plywood at the bottom of the formwork]