Random Seismic Response Analysis Of The Railway Cable-stayed Bridge Considering Static Geometric Nonlinearity

As a cable-supported load-bearing system,a cable-stayed bridge has good mechanical properties and economic indicators.It has become the main structural type of crossing rivers.In earthquake-prone areas,cable-stayed bridges are inevitably affected by random earthquakes.However,most existing seismic design analysis is based on time history analysis.The influence of seismic randomness is less considered.In addition,the static geometric nonlinearity has a specific impact on the dynamic performance of long-span cable-stayed bridges,but there are few related studies.Therefore,based on a long span railway cable-stayed bridge,this paper studies the random seismic performance of long-span cable-stayed bridges with static geometric nonlinearity.The main contents and conclusions of the research work are as follows:(1)This paper summarizes the development of long-span cable-stayed bridges at home and abroad,the evolution of seismic analysis methods,and the research status of random ground motion response.It points out the shortcomings of the existing research.(2)Taking the select the bridge as the research object,a structural dynamic analysis model considering the detailed construction process is established by using the largescale finite element software MIDAS and the influence of geometric stiffness on the dynamic characteristics of the bridge is analyzed.The research shows that the geometric stiffness has little influence on the overall model of the structure.(3)This paper introduces the calculation method of bridge seismic random response based on convolution summation,compiles the corresponding calculation program,and verifies it by comparing the calculation results with the analytical solution.(4)Using the above method,the evolution power spectrum and mean square deviation of crucial nodes and sections of the bridge in transverse,longitudinal,and vertical directions are calculated.The analysis results show that the random seismic response of the structure is mainly in the low-frequency band that 0～5Hz.The excitation evolution spectrum is the main factor that controls the peak value in the frequency domain.