基于结构多尺度分析的超大跨斜拉桥损伤定位方法研究

Damage Location Identification for a Super-Long-Span Cable-Stayed Bridge Based on Structural Multi-Scale Analysis

以苏通大桥斜拉桥的扁平钢箱梁结构为分析对象,采用子结构方法,将扁平钢箱梁结构的整体尺度动力特性和细节尺度构件损伤相互衔接,实现了超大跨斜拉桥的多尺度损伤分析。在此基础上,对模态曲率指标和模态应变能指标的损伤识别效果进行了对比分析。结果表明:采用子结构方法可以有效地实现钢箱梁局部构件损伤与整体结构响应的多尺度衔接,从而较真实地研究钢箱梁局部构件损伤对超大跨斜拉桥动力特性的影响;无噪声情况下,模态曲率指标能正确识别所有损伤工况,而模态应变能指标则对部分损伤工况的识别效果较差;模态应变能指标的抗噪声能力总体上优于模态曲率指标。

The full-scale dynamic characteristics and fine-scale local damage of steel box girder are connected by the substructuring method to realize structural multi-scale damage analysis for a super-longspan cable-stayed bridge, Sutong Cable-stayed Bridge. The modal curvature index and modal strain energy index for damage localization of steel box girder are further comparatively studied. The analysis results show that： （i） the effect of the simulated damage in various components of the steel box girder on the dynamic characteristics of a super-long-span cable-stayed bridge should be properly considered in the structural damage analyses using the multi-scale numerical computation; （ii） in the absence of noise, modal curvature index can properly identify all structural damage cases of steel box girder, whereas modal strain energy index fails to identify some damage cases; （iii） modal strain energy index is the best in anti-noise compared with modal curvature index on the whole.