Comprehensive dynamic indexes for damage detection of cable-stayed bridges

Dynamic characteristics will produce changes if damages occur in girder and cables of a cable-stayed bridge. Mode shape curvature difference method is a conventional damage detection method for cable-stayed bridges. While estimation of damage position is different under different mode shape, some damage positions may be misjudged or missed under some mode shapes. For damage in different part, it is not known which mode shape is precise and should be adopted. It is necessary to develop a comprehensive dynamic damage index for detecting different kinds of damages. In this paper, frequency changes analysis and mode shape curvature damage detection analysis are carried for damages of girder and cables firstly, and then damage detection analysis based on two proposed comprehensive dynamic indexes is performed. It is shown that the comprehensive dynamic indexes are more effective on damage detection than traditional mode shape curvature difference.