Behaviour of very long cable-stayed bridges during erection

Abstract

Stonecutters Bridge and Sutong Bridge in China have pushed the world record for main span length of cable-stayed bridges to over 1000 m. The design of these bridges, both located in typhoon-prone regions, was strongly influenced by wind effects during erection. Rigorous wind tunnel test programmes were devised and executed to determine the aerodynamic behaviour of the structures in the most critical erection conditions. Testing was augmented by analytical and numerical analyses to verify the safety of the structures throughout construction and to ensure that no serviceability problems would affect the erection process. This paper outlines the wind properties assumed for the bridge sites, the experimental test programme with some of its results, the dynamic properties of the bridges during free-cantilevering erection and an assessment of their aerodynamic performance. The similarities and some revealing differences between the two bridges in terms of their dynamic response to wind action are also discussed.