Wind Charateristics and Response of Tsing Ma Bridge During Typhoon Victor

Abstract

This chapter analyzes the wind and structural response data to evaluate wind characteristics and acceleration response of the Tsing Ma Bridge in Hong Kong. The results show that during Typhoon Victor, both mean and turbulent wind characteristics varied considerably due to the change of wind direction and the upwind terrain. Turbulence intensities and gust factors measured during Typhoon Victor were higher than those due to seasonal trade winds. An empirical formula for gust factor as a function of turbulence intensity and time duration was also provided based on the measured results. It was confirmed that the wind excitation mechanism of the Bridge in the lateral direction was different from that in the vertical direction or the rotation. The along-wind acceleration response of the Bridge was approximately proportional to mean wind speed square, while the vertical acceleration and torsional angular acceleration were almost proportional to mean wind speed cubic. The natural frequencies identified from the acceleration response spectra were consistent with those obtained from the ambient vibration measurement or the numerical analysis.