THE STRUCTURAL DESIGN OF THE MEGA TOWER, CHINA WORLD TRADE CENTRE PHASE 3, BEIJING CHINA

The Mega Tower, China World Trade Centre Phase 3, Beijing China is 330m high and composed of a five-star hotel, grade-A office levels and multi-purpose spaces. The height of the building and the high seismic design intensity in Beijing poses a great challenge to the structural engineers, especially considering various stringent requirements by Chinese codes. Various structural types, utilising different materials, have been explored until the final design was accomplished, which comprises a composite braced frame core and a composite perimeter frame, linked by two outrigger systems at relevant E&M floors. The tapered elevation of the tower building necessitates three transfer belt trusses that allow the reduction in number of perimeter columns in middle and high zone of the tower. The use of 8 storeys high V-shaped columns with transfer belt truss admit of the grand entrances with wide spacing of columns at ground floor for the five-star hotel and grade-A office, and meanwhile provide a smooth structural transition to the perimeter moment frame above. Composite elements of various types are extensively used and positioned carefully to satisfy the combined requirements for stiffness, ductility, redundancy, and cost-effectiveness. The composite steel plate wall (C-SPW) is implemented in the structure, possibly the first time in China, to increase the shear capacity and stiffness and improve the ductile behaviour at specific zone. Accurate finite-element analysis and advanced non-linear elasto-plastic time history analysis have been carried out to evaluate the structural behaviour and ensure the building safety under different seismic levels.