Comparative study of damage locating indices for cable-stayed bridges

This paper presents a comparative study of using the modal curvature index, the modal flexibility index and the cable tension index for damage localization in the cable-stayed Kap Shui Mun Bridge. Based on a precise and validated three-dimensional finite element model of the bridge, a series of damage cases associated with the deck are introduced in the simulation study. The simulation study is conducted with the following focuses: (i) performance comparison of the three indices in the absence of noise; (ii) sensitivity of three indices to damage extent; (iii) tolerance of the three indices to noise. The analysis results show that, for different damage types, modal curvature index and modal flexibility index are complementary to each other in damage indication. Comparatively, cable tension index is more stable than the other two indices to damage extent. For most damage cases, flexibility index is the best of the three indices in anti-noise and the curvature index is the worst.