Damage Detection in the Cable Structures of a Bridge Using the Virtual Distortion Method

This study investigated damage detection of cable structures in bridge engineering using the virtual distortion method (VDM). The main theory of damage detection based on the VDM, including the influence matrix, the stiffness reduction, and an optimized algorithm, was applied to damage detection in hangers in a real three-dimensional finite-element model (FEM) of an existing arch bridge. Two damage-detection methods for hangers were used. One method is based on the static VDM, which has high precision but requires more sensors. The other method is based on the dynamic VDM, which does not require many sensors but has a lower precision. The effectiveness of damage detection in hangers was investigated through a numerical simulation. The steps of damage detection that can be combined with practical engineering were determined. The anti-interference ability of the wind load, the optimal placement of sensors, and the antinoise capability were considered in the case study. It was verified that the proposed methods can rapidly and accurately identify the damage location and degree of damage. (C) 2017 American Society of Civil Engineers.