STRUCTURAL DESIGN CHALLENGES FOR TWIN TOWER OF 'GATE TO THE EAST', SUZHOU CHINA

摘要

The 280m high twin tower is the key component of the prominent development, "Gate To The East", Suzhou China. With the theme of being a "Gate to the East", two towers, which are of same height but have different number of storeys, will stand 60m apart at ground level and link together at top 8 floors. The underground light rail transit system will pass right through the "gate" formed by the twin tower. Each tower mainly comprises a reinforced concrete core and composite perimeter columns, linked together by belt trusses and outriggers system at three different mechanical and refuge floors. The continuous change in tower profile from bottom to top necessitates the extensive transfer structures in the middle and high zone of the tower for supporting the additional columns. Among those transfer structures, the long span linking structure located at level of approximately 240m above ground for supporting the top 8 floors between two towers provided the greatest engineering challenge of the project to structural engineers, primarily resulting from that the top linking structure would be subjected to a variety of structural responses arising from gravitational load, wind load, seismic load as well as differential shortening of the towers. Extensive studies have been carried out to evaluate the structural behaviour of the twin tower structure, prior to arriving at the final design of the twin tower structure. This paper will outline how the structural design resolved these engineering challenges, with the focus on those driven by the top linking structure, and meanwhile addressed the architectural, functional as well as economic considerations.