ASSESSMENT OF FATIGUE DAMAGE IN THE TSING MA BRIDGE UNDER TRAFFIC LOADINGS BY FINITE ELEMENT METHOD

摘要

Steel bridges are vulnerable to fatigue damage caused by traffic loadings. The Tsing Ma Bridge (TMB) in Hong Kong, of 2.2 km total length and a main span of 1377 m, is the longest steel suspension bridge in the world carrying both road and rail traffic. This paper is aimed to study the fatigue damage of the TMB using the Finite Element Method. An effective finite element (FE) model of TMB embodying the properties of almost all the structural members was developed. The verification of the model was carried out with the help of online data. The dynamic response of the TMB under traffic loading was analyzed using the developed FE model. Considering the bridge fatigue damage is local damage, a local damage model is applied in the FE model of the TMB with possible fatigue damage degree and its evolution equation. As the TMB is at its virgin state and the traffic volume on the bridge is relatively light, an update ratio of the traffic volume is also considered in the proposed FE model. With the established FE model, the future response of the Bridge could be simulated and, the damage degree in the Bridge under traffic loading could be assessed too. All of these results provide a basis of estimating the remaining service life of the TMB.