Research On Dynamic Behavior Of A Railway Partially Cable-stayed Bridge Under Seismic Action

The partially cable-stayed bridge is a new type of structure emerging in recent years. It is a composite structure between a continuous beam bridge and a cable-stayed bridge. Due to frequent earthquakes, the seismic capacity of bridge structures have become a growing topic of concern. Therefore, it is necessary to do some researches on dynamic characteristics and seismic response of such a partially cable-stayed bridge, which can provide reference and basis for its application in China high-speed railway. The main contents are as follows:(1) Based on the summary of the development of the partially cable-stayed bridge, vehicle-bridge coupled vibration at home and abroad, it describes the necessity of the study on vehicle-bridge coupled vibration systems under earthquake for the partially cable-stayed bridge.(2) A3-D finite element model is established by finite element software ANSYS for the Dongping Waterway partially cable-stayed bridge. The natural vibration frequencies and modes of the bridge are thus calculated and analysed.(3) The high-speed train loads are simpliflied as a series of moving concentrated forces which are ranged according to the actual wheelbase. The dynamic responses of the bridge are calculated by self programming.(4) The dynamic responses of the bridge under two high-speed trains (ICE-3and CRH-2) at different speeds are compared.(5) Taking the displacement seismic wave as the input of the system, the influence of traveling wave effect on Dongping Waterway partially cable-stayed bridge is analyzed.(6) Finally? the influence law of the seismic intensity on the dynamic responses of the bridge is studied. The results show:the seismis intensity has a great influence on the dynamic of the bridge. The dynamic responses will increase linearly with the increasing intensity.