Conversation on making and constructing

ENTREENTRE is a new platform and digital magazine for architecture and image. It is edited and curated by Danish architects Frederik Petersen, Karen Gamborg Knudsen and Anne Friis.

The very first issue is an hour-long conversation with Professor Mark West, the pioneer of fabric formwork who is also a very dedicated maker and and amazingly skilled at drawing

The issue is a sound-file where Mark West is interviewed by Frederik and some of the images discussed during the conversation are shown on the page and you can scroll through the images as you listen.

Check it out here - and prepare to listen more than once on the development of hallucinating and 'self-made' drawings, construction pieces and work in graphite, fabric and concrete.

EntreEntre also organizes exhibits - and the second issue supplements an exhibit at the Copenhagen Architecture office and gallery Leth & Gori. Here architects Theis Dreiby and Nat Chard exhibited drawings and models investigating representation and making architecture.

[Mark West, Blackout Everything Falls]

[Mark West, Safehouse]

[Mark West, Casa del Fascio redrawn]

Flying Carpets – Foster’s Concrete Canopies

A good while back I had the great opportunity to visit the Kingdom of Jordan and  dear friends of mine.
Beyond visiting the out of this world amazing Petra, a few Biblical sites, beduin and desert castles  – well, the Concretely highlight was the new international airport to Ammann. Queen Alia International Airport designed by Sir Norman Foster and finished in 2013.

A nice opportunity to search into the construction of the airport came when asked to lecture about concrete as an architectural material at the Royal Danish Academy of Fine Arts, School of Architecture.

[Great light, grand spaces, and nice temperature - but was this really prefab or cast on site? Image by Yours Concretely]

[The modular design of tessellated roof canopies allows for a planned expansion of the airport, canopy by canopy. Image via]

[Detail of the column head. Really tight and great surfaces. Image by Yours Concretely]

[The large outdoor area - in the poor image taken with my mobile phone, the tessellated canopies appear to continue. Image by Yours Concretely]

[Images of Queen Alia Intl Airport. Photos by Anne-Mette Manelius, Yours Concretely]

Cast in place or prefab elements?
The search was initiated from my wonder - how were the gigantic canopy-like vaulted ceilings actually made? It was puzzling because the structure appeared, at the same time, to be cast in place and cast as prefabricated concrete elements. The details and connections as well as the finish of the concrete is of much higher quality than anything else I had seen in Jordan. – furthermore,  there are clearly defined connections between structural elements. All indicating the use of prefabricated concrete.

Structurally, on the other hand, such large-spanning vaults are traditionally constructed as cast in place. Also – were these huge structure made from elements, - the cranes and trucks to deliver them would have had to be enormous. Furthermore, the price of human labor – a crucial ingredient in concrete, Adrian Forty reminds us – would be fairly low in Jordan.

A visit to the airport’s Wikipedia-page added weight to my ponder as it stated how the airport is composed of 127 concrete domes, each weighing up to 600 metric tonnes”

[Detail of the ceiling with acoustic elements mounted on the concrete - oh concrete bliss. Photo by Yours Concretely]

Cast in place AND as prefab
The beauty of concrete is that it comes in many forms and properties - and the revelation is that the structure is cast as prefab as well as cast on sight. High performance fiber-reinforced concrete (HPC) was used to make the  stay-in-place formwork elements. They were thin double-curved concrete shells cast in molds made in a factory in Greece. Here shipbuilding skills were used to develop the curves.

The challenge for these elements comes down to this: at the end, the hardened concrete structure of each canopy will function as one. Yet the most challenging loads impact the elements during construction as well as transportation from abroad. The construction of the airport using prefabricated concrete molds was possible with the development of high performance concrete.

[Images from the engineering of the high performance fiber-reinforced (HPC) concrete shells. Images above are via Greek consultants Cubus Hellas]

Behind the scenes
I enjoy the construction of architecture, so I always enjoy the process more than the final result. With impressive works such as this one, I want to see the "making of" images. The British Concrete Quarterly ran a nice article on the project with lots of facts that you can open here – yet no images from construction. Below is a collection of images that I have found on web sites of contributors
to the project.

[Image of Queen Alia Airport under construction. Via 'High Contrast' Wikimedia]

[Montage of hollow fibre-reinforced concrete elements. Via Joannou & Paraskevaides]

[Images from the engineering of the high performance fiber-reinforced (HPC) concrete shells. Image via Greek consultants Cubus Hellas]

Project: Queen Alia International New Airport (2005-2012)

Client: The Hashemite Kingdom of Jordan Ministry of Transport 

Architect: Foster + Partners

Structural and MEP engineer: Buro Happold

Contractor: Joannou & Paraskevaides 

Reused concrete - 6 points towards a rolling circular economy

The circular economy is recent years' sustainability buzzword. For concrete, it is an essential and ongoing search for better used of the raw materials (first generation) as well as the second generation materials.

[Image of the demolition of a large movie theater, Photo by Trondur Dalsgaard via Fyens.dk]

Recycling seen from the heavy industry
Recycling and resource economy is not my speciality. So, leading up to my previous post about recycling concrete, I interviewed leading voices of the Danish concrete industry. Known to be as heavy an industry to move anywhere as their product when hardened, the opinion here is that business as usual is good. And reuse as excellent road-fill cannot be topped as the best - and only way to reuse the sky-high 95% of the concrete waste from infrastructure and buildings. It is nice to extend the life of the material yet it is unlikely to enter an extra cycle of use from here.

[Mixed concrete and asphalt waste. Image via] 

Since this is my private blog, however, there is room to have doubts about this single and and, let's admit it, single-minded opinion.

I have lately attended a number of recycling conferences. I have collected six points towards a better circular economy for concrete.

1. Know the source and the quality of your second generation material. This is the great challenge for all materials in construction. It is a matter of strength for construction materials, and to locate beautiful old windows treated with lead-based paint, railway sleepers with all sorts of nasty heavy metals, concrete with PCB, etc.

2. No extra cement to compensate. New concrete made from a mix of first and second generation concrete materials (gravel, sand, and larger aggregate) has been made and without using the extra cement to compensate for unknown qualities. - it is not a commercial practice.

3. New structures need not be constructed to last 100 years. The Danish industry produces high-quality concrete. Producing concrete of a slightly lower quality may be the consequence of using secondary materials - and this may be just fine.

4. Empirical tests
Concrete strength is always tested for any batch of mixed construction concrete - for reused concrete as well.

[Image of compression test of concrete cylinder via]

[Numerous cylinders are cast and tested for all construction projects. Image via]

5. National regulations need to change approach from 'construction waste' to  'construction resource' The national regulations for waste materials were developed as such, that is - looking at second generation materials as waste and not resources. This means that rules are too strict to work with in practice.

6. Show me the money
New national strategy for resource efficiency point at a more material conscious practice that should be simple 'and only cost a bit more' as a speaker from the secretary of the environment said during a presentation. This is obviously a major challenge - who should pick this extra expense? And why not make economic incentives to reuse more? If you can run a business, there is a market.

In the 1970s demolition companies would actually bid how much they would pay to enter their projects because buildings contained value that these 'material brokers' would disassemble and cash in on. - today it is the opposite. It is expensive for clients to demolish buildings. - When we see the change back, it will be a sign that the circular resource agenda is actually on its way, rolling.