The Infinity Footbridge

This paper reports on the design of the Theme Pavilion for the Shanghai World Expo 2010. The Pavilion has plan dimensions of 218m x 288m and its western exhibition hall, with a column-free space covering 126m x 180m, will be one of the largest halls in China. As no expansion joints were allowed, the main structural problem was coping with thermal effects. Horizontal seismic resistance was also a key issue. For the final design, a126m-span truss string structure was used (a truss with an underlying pretensioned cable) and the supporting frame below was stabilised via a mixture of conventional braced bays combined with energy dissipating systems. The paper discusses some special issues, including cable pretension force selection, joints for the cable-strut system, roof support, frame bracing and control of global temperature actions. Suggestions about these issues are put forward for optimising the roof and frame structural behaviour whilst making the construction stage easier and reducing costs. Professor Jiemin Ding Architectural Design and Research Institute of Tongji University, Shanghai, China Dr Honglei Wu Architectural Design and Research Institute of Tongji University , Shanghai, China Zhijun He Engineer, Architectural Design and Research Institute of Tongji University, Shanghai, China Yuerong Wan Engineer, Architectural Design and Research Institute of Tongji University, Shanghai, China

I am very humbled to be here tonight to receive the Gold Medal from the Institution of Structural Engineers. The Institution is unequalled as a professional organisation of structural engineers. To be a Fellow was one of my lifetime goals; to receive the Gold Medal was beyond my dreams. The list of previous recipients of the Gold Medal includes the names of engineers I have admired throughout my entire professional career. It is especially poignant to receive the award in London, as modern structural engineering was essentially invented in Great Britain during the Industrial Revolution. As highways and railroads spread across the country, rivers and valleys needed to be crossed on bridges that could bear heavy loads. In response to this need, British engineers of the period left us with structures that demonstrate they had very clear ideas of function and form. Long before any of the modern computational tools we currently have, these individuals were creating structures that are beautiful, elegant, and intellectually correct based on first principles and a fundamental understanding of structures. William F. Baker, PE, CE, SE, BSc, MSc, FIStructE, FASCE Partner, Skidmore, Owings and Merrill LLP, Chicago