Seismic Response Analysis Of Long-span Flexible Suspension Bridge

In recent years,a large number of pedestrian suspension bridges for pedestrian sightseeing have emerged in the high mountain and canyon areas and scenic spots in the western part of China.Chongqing Chengkou pedestrian landscape bridge is a large-span non tower asymmetric pedestrian suspension bridge.Because of its strong spanning capacity,light weight,convenient anchoring,beautiful appearance and other advantages,it adopts this new type of bridge.At present,most of the researches on this type of pedestrian suspension bridge at home and abroad focus on the aspects of static wind stability,human induced vibration and comfort of the bridge,but the researches on earthquake resistance are far from enough.Based on this,this paper analyzes the dynamic characteristics and seismic response of the large-span non tower asymmetric pedestrian suspension bridge with the main span of 382 m in Chengkou County of Chongqing as the engineering background The related contents are as follows:(1)This paper discusses the general situation of the development of pedestrian suspension bridge and the theory of seismic response analysis.ABAQUS finite element is used to model the pedestrian suspension bridge and determine its completion state.On the basis of determining the reasonable completion state,subspace iteration method is used to carry out modal analysis,analyze its dynamic characteristics,obtain the natural frequency and mode of the structure,and provide the basis for the subsequent response spectrum analysis.(2)According to the geological conditions of the bridge site,the seismic parameters of the bridge are consulted,and the natural frequency obtained from the previous modal analysis is used to draw the horizontal acceleration response spectrum curves under the two kinds of seismic actions of E1 and E2 respectively,and the seismic response of the bridge under different working conditions is calculated considering the two-way combined seismic action.(3)This paper discusses the synthetic method of artificial seismic wave,using this method to synthesize the artificial seismic time history curve corresponding to the design response spectrum of the code,and carries on the linear time history analysis under the uniform excitation to the pedestrian suspension bridge,finally obtains the main response history and peak value of the bridge structure under different working conditions.The results of response spectrum method and time history analysis method are compared,and the most unfavorable components,positions and working conditions of the bridge type are obtained.(4)The effect of non-uniform excitation considering traveling wave effect on pedestrian suspension bridge.Because the span of pedestrian suspension bridge is large along the bridge direction,it is of little significance to consider the traveling wave effect of lateral or vertical ground motion.Therefore,the analysis only considers the phase difference of longitudinal ground motion,does not consider the attenuation of amplitude,and studies the influence of different traveling speed on pedestrian suspension bridge.