Travelling-wave Effect Analysis Of Caiyuanba Changjiang River Bridge In Chongqing

In recent years,earthquake disaster frequently occurred in whole world which brought great damage to the safety of life and property for people.If the bridges which looked as very important structures by people for connecting with people's life collapsed caused by earthquake,the indirect disaster will take up to bring more loss of life and property.Now, we usually employ the response spectrum analysis which is defined in the earthquake-resistance code for bridge design. The method only considers bridge,s responses to uniform excitation of earthquake. In fact, because the different supporting points bear the variant earthquake motion witch are produced by variant hypocenter,earthquake wave propagation path and ground.In this thesis,I mainly consider the three aspects in earthquake analysis:the ways of earthquake inputting,the bridge,s characters,bridge,s earthquake response. considering traveling-wave earthquake response were studied as follows On the basis of the study achievements at home and abroad and on the basis of Caiyuanba Changjiang River bridge of Chongqing City;â‘ The study of analysis approach of earthquake response. Several analysis methods used to calculate the earthquake response of bridges,such as the time-history approach, the response spectrum approach, random vibration approach, are introduced and discussed. The practical application of dynamic balance equations of multipoint excitation are studied and discussed in this paper; Responsible formulations were used to describe the bridges' dynamic actions and appropriate method was chosen to solve these problems on the base of structural dynamics researches;â‘¡The finite element model of the structure was formed through reasonable simplification. And structural dynamic properties were calculated by using the famous program of ANSYS. Structural dynamic properties were performed;â‘¢The responses to uniform excitation of earthquake about the Caiyuanba Changjiang River were analysed. Structural seismic responses that seismic wave was inputted from vertical direction were discussed. Internal forces and displacements of structural crucial sections were compared. Some beneficial conclusions were gained;â‘£The responses to travelling-wave effect of earthquake about Caiyuanba Changjiang River were analysed. In this study,the contrast of the multpiont excitation to uniform excitation ,the conclusion is that the travelling-wave effect is very important for Caiyuanba Changjiang River.1) The different wave speeds produce variant effects.In general ,the litter is the wave speed,the bigger effect is the internal force and displacement,but the differnt wave speed cause the variant effect.And between different waves delay phenomena is occured. The time is decided by the direction of the transmiting earthquakes wave. 2) It is very obviously that bridge,internal force and displacement have grate change caused by trvelling-wave. especially in main arch,the effects are very obviously.in amount The responses to travelling-wave effect of earthquake benefit to the the internal force of bridge, steel construction,but it is bad for main arch.