CMG Headquarters - Steel Fiber Reinforced Concrete Structure
Updated: Aug 17, 2020
Location: East Third Ring Road Guanghua Road Beijing, China
Construction dates: 1 June 2004 - 16 May 2012
Floor count: 51
Roof: 234 m (768 ft)
Floor area: 389,079 m2 (4,188,010 sq ft)
Developer: China Media Group
Architect: Rem Koolhaas and Ole Scheeren: Office for Metropolitan Architecture East China Architectural Design & Research Institute
Structural engineer: Ove Arup & Partners.
Main contractor: China State Construction and Engineering Corporation.
The new headquarters of China Central Television (CCTV) is a 234m tall building with a highly unusual shape, described as a 'three-dimensional cranked loop'. The building is formed by two leaning towers, bent 90° at the top and bottom to form a continuous tube.
The building’s primary support is achieved through the irregular grid on its surface, a visible expression of the forces travelling through the tube structure; the smaller the diagonal pattern, the stronger the load and the greater the support.
“The bracing arrangement is reflected in the façade design, providing a visible representation of the complex force distribution throughout the building structure. ”
The braced tube structure also gives the building the required robustness to withstand the likely seismic activity in the area and therefore provides an extra level of safety.
Engineering System 🏗
Αll the structural support elements in the building are of structural steel, except some external columns are steel-reinforced concrete columns due to the magnitude of loads they are designed to carry. The floors are composite slabs on steel beams.
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From the onset, it was decided to adopt an external skin of leaning columns, horizontal edge beams and triangulated bracing on a two-storey pattern to form an enclosed tube structure to support the building. Furthermore, the braced tube structure affords a multitude of alternative load paths.
Such a robustness feature is highly desirable, especially in seismically sensitive Beijing. It also provides safety in the event of an extreme design incident, such as blast removal of a major column in the building.
The external diagrid structure is also boldly expressed in the building’s façade. It visually expresses the pattern of forces in the external tube, reinforcing the transparency between structure and architecture, a strong philosophy in the building’s design.
The unique diagrid pattern in the external structure was arrived at after extensive iteration and optimization, in close collaboration with the architect.
Internal Trusses were used to cope with the floor plans required,