基于环境振动测试的润扬斜拉桥索塔的有限元模拟

提出了大跨斜拉桥索塔有限元模型的阶次误差、结构误差和参数误差的分层次修正方法。根据润扬斜拉桥索塔的设计图纸,在索塔有限元模型的阶次误差分析和结构误差分析基础上,确定了索塔单元划分的数目和梁柱节点刚域的计算参数。在此基础上,采用基于灵敏度分析的模型参数修正方法,结合索塔动力特性的测试结果对索塔的初始有限元模型进行了动力修正。模型修正与验证结果表明,索塔模型参数的修正必须考虑梁柱节点刚域的影响以及修正参数的上、下限值约束。修正后的润扬斜拉桥索塔模型能全面、正确地反映索塔结构的动力特性,可作为索塔结构健康监测与安全评估的基准有限元模型。

Finite Element Modeling of the Tower of Runyang Cable-stayed Bridge Based on Ambient Vibration Test

The multi-level model updating method is put forward for finite element modeling of the bridge tower for long-span cable-stayed bridge,which includes model order updating,model structure updating and model parameter updating.According to the design drawings of the tower of Runyang Cable-stayed Bridge,the element numbers of the tower and calculation parameters for nodal rigid zone are both determined based on the analysis results of the model order error and the model structure error.The finite element model of the tower is further dynamically updated according to ambient vibration test through modal sensitivity based model updating method.Model updating and verification results reveal that the model parameter updating should take nodal rigid zone and parameter modification restriction into account,on the basis of which the updated tower FE model can properly reflect the dynamic characteristics of the tower and can serve the baseline FE model for the purpose of structural health monitoring and safety evaluation.