DYNAMIC BASED CONDITION ASSESSMENT OF A CABLE-STAYED BRIDGE

摘要

San-Xian-Zhou Bridge is a reinforced concrete cable-stayed bridge, with a main span of 238m. The bridge was opened to the traffic in May, 1999. The field ambient vibration test was carried out to determine the real dynamic characteristics and cable tension of the bridge at current condition. An initial three-dimensional (3-D) finite element (FE) model of the bridge was developed to perform a theoretical modal analysis. The results obtained from the field ambient vibration testing was then used to validate and improve the initial FE model. Based on this dynamically validated FE model, the static behaviors of the bridge under the designed vehicle loading were studied. The response results obtained from this method were compared with that of the field static testing. There is a good correlation on the predicted behavior of the bridge between two approaches. Hence, it is concluded that the dynamic-based condition assessment method presented in this work is able to successfully predict the performance of the bridge at current condition. It is demonstrated that the target bridge can still fulfill the requirements to pass the designed vehicle loading safely. Finally, the predictions of the load-carrying capacity of the bridge under some possible damage conditions were carried out and some important conclusions are obtained.