大跨度桥梁抖振响应的现场实测研究,对桥梁风工程的发展具有重要意义。2008年7月,"凤凰"台风突袭江苏,本文以遭受该台风袭击的世界第一大跨斜拉桥——苏通大桥为工程背景,综合利用现场实测风特性数据和该桥结构健康监测系统(SHMS)中加速度传感器实时采集的数据,采用频谱分析和统计方法对超大跨度斜拉桥的抖振响应进行了现场实测案例研究,主要研究内容包括桥址区的强风特性分析、主梁和拉索振动响应特性分析、振动与风速的关系、上下游拉索的振动特性对比以及斜拉索阻尼器的减振效果分析等。研究结果可用于验证现有抖振理论分析方法的可靠性,同时可为超大跨度斜拉桥的抗风设计提供参考。
Field measurement of buffeting response of long span bridges is of great significance to the development of bridge wind engineering. The Sutong Cable-stayed Bridge (SCB), as the longest cable-stayed bridge in the world, is taken as an example. When typhoon Fung-Wong passed through Jiangsu in July 2008, field measurement of the typhoon characteristics was conducted and the structural vibration responses were wholly recorded by the SHMS. Based on the frequency spectrum technique and statistical theory, the measurement data are analyzed to obtain the wind characteristics, the vibration response characteristics of the stay cable and the deck, the variation of acceleration response RMS vs. wind velocity, the vibration response characteristics comparison between upstream and downstream stay cables, the vibration control efficiency of the dampers on the stay cables, etc. The results can be employed to validate the reliability of current buffeting response calculation techniques, and provide references for wind-resistant design of the super-long-span cable-stayed bridges.