The Earthquake Response Analysis Of Urban Viaduct With Unseating Prevention Devices

The fall-beam destruction in the earthquake is devastating. At present, the collapse-proof systems are researched positively in some countries. The development of the collapse-proof systems is coming in recent decades, It is in the just beginning stages. Japan and the United States research early. The development of unseating prevention devices is more perfect. But the development of unseating prevention devices in China is only beginning. It has a important meaning to research out the effective unseating prevention device to prevent Falling beam.Based on the above objectives, this paper do a design of the unseating prevention devices and Time process analysis is done for a urban viaduct of Lanzhou city. The studies and results in this dissertation are summarized as follows:(1) The destruction of the bridge structure in the earthquake and the development of the unseating prevention devices are introduced at home and abroad.(2) the basic seismic theories of the bridge are summarized, the rationale about the static method, response spectrum method and Time process analysis method are collated. And, the analogy method of the structure are summarized. It mainly includes Piers elastic-plastic model, Bearing nonlinear model, Collision unit model and unseating prevention devices model. Then, the design method of the unseating prevention devices are proposed. Mainly, the design earthquake force are calculated, the attended mode of the unseating prevention devices are selected, and also the cable quantity, and cable length, the interstice size are selected.(3) A comparative analysis are done for a urban viaduct of Lanzhou city, under the circumstances of no unseating prevention devices, Three kinds of calculation model are set up. Through the comparative analysis of the three kinds of calculation model, the effect of friction at supports are obtained.(4) in the base of three models, the unseating prevention devices are added. A comparative analysis are done for the model about unseating prevention devices in the condition of strong earthquakes. Through the comparative analysis of the two kinds of model about having and not having the unseating prevention devices, the effectiveness of the unseating prevention devices are checked, the results showed that even the unseating prevention devices can easily control relative displacement of pier-beam, and meet with the requirements of the combine length of pier-beam.(5)By changing the design parameters value, the influence of the unseating prevention devices to structural internal force and deformation are obtained. The design parameters including the different attended mode, the different cable length, and the different interstice size. In the end, the Comprehensive analysis are to be done about the design parameters of the unseating prevention devices.