Seismic Response Analysis Of Multiple-point Excitation On Large-span Steel Arch Bridge

Damage of the bridges in all previous earthquakes definitely unfold the deficiency ofseismic technology, After suffering the quake in Osaka and Kobe, a high attention have beenfocused on the serious shaking phenomenon of the steel structure bridges. So, it is necessary tostudy and master the seismic response of bridge for establishing reasonable seismic designsystem and adopting effective seismic measure.In this thesis, on the basis of the study achievements at home and abroad, on the basis ofNiu-Gen Bridge of Japan, long span concrete filled steel arch bridge earthquake response werestudied, then a spatial finite element model for the bridge is established by the ANSYS software,and referring to the seismic design theory of large-span bridges,the bridge model characteristicsand dynamic behavior are both analyzed by using the time-history analysis method.In allusionto confirm the influences of nonlinearity interaction to seismic behavior of the bridge structure,athree-dimensional time history analysis for the bridge is investigated,and combine to thenonlinearity factor,study the factors of the multipoint excitation for the bridge.When considering the compulsory evaluation of nonlinearity behavior,calculated two casesaccording to the difference location: In this situation,along in length and plumb,the foundationsoil is considered to be rigid in general seismic analysis, and the material nonlinearity of thebridge is analyzed by introducing a relatively simple analysis method.To prove the earthquakeresistant performance of the superstructure,the substructure is assumed to be in elastic stagewhen the earthquake response analysis of the superstructure is made.Considering thedevelopment of the plastic area in the superstructure cannot be explicitly predicted,its plastichinge is located first based on the above elastic analysis.Then by introducing plasticparameters,the nonlinear earthquakere sponse analysis is conducted,and the expansion of theplastic range is checked out in order to confirm the safety of the bridge structure.In this way,theearthquake response behavior evaluation of the bridge could be reflected more exactly both instrength and ductility.Finally,the seismic response behavior of the bridge model is studied under theasynchronous seismic excitation,primary considering the traveling wave effect.And the effect ofdifferent wave velocity to the displacement and element force is studied.The result indicates that the effect of transverse seismic excitation to the displacement of the traveling-wave direction isobvious and the effect to the element force is also negative. If the wave velocity is slower, theeffect to the displacement and element force are more obvious. So it is necessary to consider theseismic traveling wave effect of long span arch bridge.