December 2, 2007

Technology molding existing materials

In this search for the impact technology has had in recent history towards traditional materials, we have found that three materials in specific have been the most extensively used in construction throughout the world: concrete, bricks and wood are the most representative and the most used.

“Concrete, the solid that forms at room temperature from mixing a grey powder (mainly Portland cement) with water and aggregates, is the most widely used material on Earth. Current estimates of world cement manufacture are around 1.7 billion tons/year, enough to produce well over 6 cu km) of concrete per year or at least 1 cu m) per person. The demand is rising: conservative estimates predict a cement demand of 3.5 to 5 billion tons/year in 2050.”[1]

By this assumption, we know for a fact, that concrete is one of the materials which needs priority in its relation with technologies, for improvement in its performance, capabilities, possibilities, and relation with the environment. So in order to improve this product, there have been a series of advances and appliances that have made concrete more useful and advanced than never before.

Basically what we know is that concrete advances happen in some specific areas:

-Material performance (structural)
-Material innovation (mixing with other materials to define new uses or new applications)
-Material Impact(environment)

We have several examples in which concrete receives new treatments which allow it to perform in ways we have never seen before:

-Light Transmitting Concrete
-Concrete as a Display
-Bendable Concrete

In addition to this specific applications to concrete, we have a number of additives and chemicals which specifically engineered, can solve problems in construction that can be directly linked to the architectural project, we were very interested in a specific building, which was conceived by Zaha Hadid, the Science Centre Wolfsburg in Wolfsburg, Germany, and solved in its engineering by AKT. What becomes really interesting is that the concrete design and pouring where specifically designed to solve the complexity of the project.

Volumetrically, the building is structured in such a way that it maintains a large degree of transparency and porosity on the ground since the main volume, the exhibition-scope, is raised thus covering an outdoor public plaza with a variety of commercial and cultural functions which reside in the structural concrete cones.

An artificial crate like landscape is developed inside the open exhibition space allowing diagonal views to the different levels of the exhibition-scope, while volumes, which protrude, accommodate other functions of the science center. A glazed public wormhole-like extension of the existing bridge flows through the building allowing views to and from the exhibition space.

The building consists of a basement car park out of which rise 10 reinforced concrete cones, flaring out to support the main exhibition space, two stories above. Each cone is of a different geometric shape, and they all change shape as they rise. Four of the cones continue through the exhibition concourse to support the steel framed, metal-clad roof. The cone walls are inclined up to 45°, which blurs the boundaries between walls and floors.

AKT treated the whole bulging as a single entity, and then analyze it for gravity loads, thermal loads and shrinkage in one model. Although the basic construction method is traditional, the engineer specified concrete with a self compacting admixture for the cone walls and parts of the course slab. There were two main reasons, the height of the pours and the inclination of some walls. The external walls of the cones are only 300mm thick, and since are heavily reinforced they had to use a self compacting admixture gels because it would have been impossible to use a traditional poker to compact the concrete.
Since the structure was designed as a single entity, ad the cones and slab are so dependent on each other for support, the whole structure had to be propped until the entire concourse slab had been poured.

[1] Concrete, New and Improved, by Prof. Franz-Josef Ulm, adapted from a speech at MIT Family Weekend, Oct. 13, 2006.

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