Beijing’s CCTV building: an engineering challenge

The project of the Central Chinese Television CCTV headquarters in Beijing is currently under construction. It has an estimated construction cost of $600 million, and it should be completed in time for the Beijing Olympics this year. However, rumors annouce it will not be ready before summer 2009.

The project is being executed by a combined Arup team from East Asia and Europe Divisions.

Arup provides the engineering design services for the structure. It is a sub-consultant to the Office for Metroplitan Architecture (OMA) led by Rem Koolhaas, which was awarded the design contract at the end of 2002 after an international architectural design competition. The construction began in December 2004.

The building is formed by two leaning towers, which are bent 90º at the top and bottom to meet in the air forming a continuous ‘tube’. As you can imagine, this is the biggest challenge for the engineers. An apparent diagrid system is used on the external faces of the building in order to make a tubular structure that resists well the important torsion and flexion. You can see that the pattern of diagonals reflects well the distribution of forces on the building’s surface.

Two other engineering challenger were that the skyscraper is built in a seismic region, and that the Chinese design codes could not be applied to such a design. It needs a resistance to intensity 8 with peak ground acceleration of 0.2g.

The standard systems for engineering gravity and lateral loads in buildings didn’t apply to the CCTV building, which is formed by two leaning towers, each bent 90 degrees at the top and bottom to form a continuous loop.