Full Model Wind Tunnel Study on the Xia-Zhang Bridge Under Operation Stage

Abstract

Problem statement: Long-span cable-stayed bridges under service and particular construction conditions are very susceptible to wind action due to their great flexibility, so the aerodynamic stability is becoming a major concern in the design and construction phrases. Cable-stayed bridges may exhibit wind-induced vibration phenomena such as flutter, buffeting and vortex oscillation under wind excitation. The study concentrated on the issues concerning the aerodynamic response of Xia-Zhang cable-stayed Bridge to make it safe and stable under wind action. Although there have been accumulating experience in the building of cable-stayed bridges and research on wind-resistant stability in Chinese Mainland, most of the research focuses on inland cable-stayed bridges or littoral ones of mid-length, but not on littoral ones whose main span is over 600 m. Therefore, wind-resistant performance research of north branch bridge of Xia-Zhang cross-sea Bridges is very necessary and important for its wind-resistant stability, safety and applicability in the operation condition. Approach: This study mainly presented the wind tunnel test program of the Xia-Zhang Bridge aeroelastic full model, including test method, test contents, test results and so on. Results: The test results contained Root Mean Square (RMS) of accelerations and displacements as well as average values of displacements. Conclusion: The conclusions were as follows: (a) In the uniform flow field, under the condition of entire bridge without rail may vibration divergence occur when α = 3°, V>122 m sec^-1. (b) No vortex-induced vibration with extreme amplitudes or static collapsing was detected in all the testing conditions. (c) In the turbulent flow field, there were very obvious buffeting phenomena. Responses to turbulence are quite intense.