Dwarf Tower Cable-stayed Bridge Under Earthquake Axle Coupled Vibration Study

Low tower cable-stayed bridge (Partially cable-stayed bridge) is a new type of structure emerging in recent years. As a composite structure system, low tower cable-stayed bridges' mechanical characteristic lies between beam continuous bridge and cable-stayed bridge. At the same time, China is an earthquake country. Thus, it is necessary to study the dynamic response of the verhicle-low tower cable-stayed bridges system under earthquake. With a three-span low tower cable-stayed bridge as engeneering background, the works completed in this paper are as the following:1. With the summary of the development of the low tower cable-stayed bridge, vehicle-bridge coupled vibration and vehicle-bridge coupled vibration under earthquake at home and abroad, it describes the necessity of the study on vehicle-bridge coupled vibration systems under earthquake.2. Based on the principle of tota) potential energy with stationary value in elastic system dynamics and the "set in right position" rule for formulating system matrixes, the corresponding bridge analysis model is established. Acoording to the mechanical characteristics of the components of the low tower cable-stayed bridge, the whole bridge model accord with the actual condition is established and used to the dynamic characteristic analysis.3. Based on the above analysis models, it comparatively analyses the dynamic response of the bridge and vehicle with single-line (ICE3 high-speed trains, domestic force C300 and E500 in Japan) at different speeds in two cases, which are with earthquake and no earthquake. Finally it comes to the conclusion: The security of moving train can be assured whether in the absence of earthquake or under small earthquake, and can't be assured under the moderate earthquake and intense earthquake function.4. It also analyses the influence law of dynamic response of the vehicle-bridge system affected by the train speed and the seismic intensity under earthhquke. The results show that the seismic intensities have a great influence on both the dynamic responses of the bridge and the vehicle, while the train speeds affect the dynamic response of the vehicle more than the bridge.