大跨度斜拉桥环境振动试验与分析

桥梁环境振动试验具有简单方便和花费少等优点。以青洲闽江大跨度斜拉桥为背景,介绍了通车前全桥环境激励动力试验,采用频域峰值法和时域随机子空间识别得到了该桥的基准的动力学特性,并与三维有限元模型计算结果进行了比较,二者吻合良好。结果表明环境振动响应足以识别出该桥所感兴趣的模态,结果可作为该桥的有限元模型修正、损伤检测、使用状态评估和健康监测的基础。

Ambient Vibration Tests and Analysis of a Large Span Cable-Stayed Bridge

Bridge ambient vibration test has an advantage of being simple,fast and cheap.A full ambient vibration test of the newly constructed Qingzhou cable-stayed bridge was carried out just prior to the opening of the bridge.The dynamic properties were identified by using the peak picking of the average normalized power spectral densities in frequency-domain and stochastic subspace identification in time-domain.The experimental results agree well with those obtained from three-dimensional finite element modal analysis.It is demonstrated that the ambient vibration tests are sufficient to identify the most significant modes below 1.0 Hz for this kind of large span cable-stayed bridges. The identified dynamic properties can be served as the basis in the finite element model updating,damage detection,condition assessment and health monitoring of the bridge.