Automated Girder Rotation Assessment of High-Speed Railway Bridges for Operation Safety

Abstract

Girder rotation at the bridge support or girder end is a key deformation indicator that reflects the high-speed railway (HSR) bridge stiffness. Large rotation deformation at these locations leads to train derailment risks, bridge expansion joint degradation, and track system anomaly, which significantly affects HSR bridge operation safety. Hence, it is very assuring to assess girder rotation periodically to ensure safe operation of HSR bridges. However, the mechanical relationship between girder rotation and HSR bridge operation safety indicator is difficult to reveal owing to the high complexity of the dynamic interaction calculation, lack of design information, and lack of finite-element model in practice. To present a girder rotation assessment method that can provide reasonable guidance for HSR bridge operation safety management, a general analytical solution for the girder rotation threshold corresponding to HSR bridge operation safety limit using a train–track interaction model is first derived in this study. Then, an online virtual-loaded method based on rotation influence line is used to predict the most unfavorable effects of HSR bridges with various forms. The automated assessment is achieved by comparing effects to the threshold. Finally, an in-service long-span HSR bridge is used to verify the proposed method. The application results show that the method can periodically generate the most unfavorable rotation effect reflecting bridge stiffness and the rotation threshold reflecting operation safety, achieving long-term automated assessment during HSR bridge operation.