Research On Seismic Response Of Long-Span Cable-Stayed Bridges With Main Piers At Different Heights

Wanzhou No.3 Yangtze River Bridge is a hybrid girder cable-stayed bridge with a main span of 730m. The bridge has two main towers and the piers of the two towers are at differenent heights. The pier height of the north tower is 13.70m while the pier height of the south tower is 53.62m, thus making the bridge asymmetric, In this thesis, finite element models were created to analyze the dynamic characteristics and seismic response of the bridge. The main contents of the thesis are as follows:(1) The development of cable-stayed bridges was introduced. Besides, the seismic response researches of long-span cable stayed bridges were summarized and there were still some meaningful studies that need to be done.(2) Several bridge seismic analysis methods were introduced including static method, response spectrum method, dynamic time-history method and power spectrum method. The advantages and disadvantages of these methods were discussed.(3) Spatial finite element models of Wanzhou Yangtze River Bridge were created to analyze its free vibration characteristics. The influence of pile-soil-structure interaction on the dynamic characteristics of the bridge was discussed.(4) The seismic response of the bridge was calculated with response spectrum method and the reponse differences of the two bridge towers were analyzed. The influence of pile-soil-structure interaction on the seicmic response of the bridge was discussed. The seismic response of the two separated towers in construction stage was studied.(5) The seismic response of the bridge was calculated with dynamic time-history method and the reponse differences of the two bridge towers were analyzed. The traveling wave effect was discussed.