Located at the heart of Beijing's new CBD extension, CITIC Tower (also known as China Zun) is the tallest building in the capital city with a height of 528m, surpassing that of China World Tower – another Arup job.
The tower accommodates seven levels of basement and a mega tower of 108-storeys providing mostly office space and an observation deck with a gross floor area of 350,000m².
528m tall tower
54mx54m at its waist
The name China Zun comes from a traditional Chinese water vessel, zun, which inspired the building design. Zun, in Chinese culture, represents communal goodwill, which is appropriate for the capital city of such an important country and civilisation. The tower's smooth vertical curve gives the building a contemporary and elegant expression that will assist in maximising the floor area at the top and provide structural stability at the base.
As the leading structural engineer from schematic design stage to preliminary design stage, Arup introduced a high efficient lateral resistancy system composed of a fully braced mega frame and a concrete core. Composite steel-concrete member like composite steel plate wall and composite mega columns are also extensively utilised to minimize structural member size and increase usable floor area. With Arup's services, China Zun, is to set the new height record in the high seismic zone.
Arup also conducted complex fire analysis to ensure the robustness of the building in a fire and optimised evacuation provisions. We minimised fire separation in the grand entrance lobby linked to the adjacent cultural centre and enlarged the fire compartment on the observation deck which will have a dense occupant load.
Digital parametric design to optimise the form
Most super high-rise buildings feature their smallest dimensions at the top to reduce the wind load and seismic mass; however, China Zun’s floor plan reduces from 78m in width at the bottom to 54m at 385m which then enlarges to 70m at the top. This unique shape required substantial scheme adjustment under a complex and lengthy structural analysis. It was also carefully studied with the project architect using an advanced parametric structural design approach and BIM technology.
Connecting parametric models to structural analysis software using an Arup-developed programme allowed the effect of changing the architectural form to be analysed accurately with some critical parameters controlling the architectural functions as well as structural performance, such as the floor dimensions at ground, top and the ‘neck’, the tower profile curvature and corner round-up radius. Parametric modelling was also applied to optimise the central line of the mega columns.
Our digital tools allowed the team to explore more than 800 options in record time, resulting in the perfect geometrical consistency between perimeter structure and façades with a robust structural design.