Research & Innovation

SOM agency, Tishman Group, Mabel Wilson (GSAPP, Columbia), Angelo Bucci (Faculdade de Arquitetura e Urbanismo, São Paolo), Fernando Menis (architect), Stanley Saitowitz (University of California, Berkeley), Hans Schober (engineer, Schlaich Bergermann and Partner), Antoine Picon (Graduate School of Design, Harvard), Toshiko Mori (Graduate School of Design, Harvard), Guy Nordenson (engineer), Jesse Reiser (School of Architecture, Princeton), Ysrael A. Seinuk (School of Architecture, Cooper Union), Nanako Umemoto (architect).

Traumatic for the inhabitants, the attacks of September 11th, 2001, were an opportunity for New York to reflect on the urban development of Manhattan, a real city within a city, and on new solutions for construction.

Some of the most well-known architects in the world are involved in the project to reconstruct the World Trade Center, comprising eight towers and a memorial: Daniel Libeskind (for Tower number 1, also called "Freedom Tower"), Norman Foster (Tower number 2), Richard Rogers (Tower number 3), Fuhimiko Maki (Tower number 4), Michael Arad (the Memorial), Santiago Calitrava (the train station), etc.

As well as architectural diversity, safety is the number one issue for these constructions which are incorporating the lessons of September 11th. A novelty in a country which has always favored steel, concrete has emerged as the ideal material to meet this requirement as a result of its high resistance properties. It is used in the central core of the buildings, and everything indicates that this type of use will spread across the United States in coming years.

Completed in 2006 by SOM, the "Seven World Trade Center" (Tower number 7) responds to these safety requirements as well as the desire to construct aesthetic and more long-lasting buildings for the city of New York.
The SOM design agency has a tradition of partnerships with the art world:

• the agency commissioned artists Jenny Holzer and James Carpenter to install a bright and poetic work on the ground floor,

• a real work of art at night, the tower's envelope changes from white to blue as a result of an LED system which responds to the movement of passers-by.

The tower is the first building to be certified by the "Green Building Council" which imposes strict standards in relation to sustainable construction:

• the concrete contains less cement than traditional concrete and contains fly ash,

• water consumption is reduced and rainwater is collected to supply the green areas,

• electricity is produced using renewable energy,

• concrete is perfectly suited to New York's changing weather (in terms of temperature, humidity, etc.).

The framework is a crucial stage for any construction using concrete. It is what gives shape to what is, at the outset, purely an architectural idea. It is also the framework which allows the concrete to pass from a liquid stone state to a solid construction state.

There are two major families of framework, depending on the project's degree of complexity and creativity:

• Standard framework: used to establish standard shapes (floors, shells, etc.), this framework generally comprises metal panels or combined modular structures (metal and plywood). It has a lifecycle of hundreds of uses.

• Made-to-measure framework: made from wood or metal, this may also subsequently be covered with a mold which will give substance to the surface of the concrete.

12 to 20 hours setting time is required for traditional concrete to become sufficiently resistant to be separated from its framework.

Building in concrete therefore always involves building twice: first constructing the framework and then building the project. An example would be the Shawnessy train station in Calgary, Canada: 24 white and ultra-thin curved shell-shaped canopies (just 2 centimetres thick!) were designed by architect Enzo Vicenzino. Ductal®, the ultra-high performance concrete,  was used to build the canopies, struts, columns, beams and rain gutters. All these elements required made-to-measure framework and modeling at an early stage, just as for the work itself.

With the arrival of self-compacting and ultra-high performance concretes in recent years, advances in the workability and flow properties of concrete have dramatically altered what we can achieve in concrete construction and design. These changes coincide with flow concepts across a wide range of disciplines: economics, transport, urban planning, etc.

In this context, concrete requires focus, precision, and an ultimate willingness to see the work last - it is not a temporary material and its execution requires a view to what will likely be the next century. Present possibilities and future innovations in concrete are therefore also rooted in time.

The use of concrete is itself part of a procedure with several distinct stages, from research on the nanometric scale to construction, via pre-fabrication.

With the advantage of its complexity and its numerous properties, concrete is moving from being simply a useful material to being a high-tech product, with a variety of ranges: this change marks a real turning point in the history of concrete!

Concrete can already be adapted to different economies, but numerous discoveries and combinations are still to emerge. Studied in-depth, made to measure, existing in a range of 500 different formulas, concrete still retains all the mystery of its evolutions...