Analysis Of Stationary Stochastic Response Of PC Composite Box Girder Bridge With Corrugared Steel Webs Under Multi-dimensional And Multi-point Earthquake Excitation

The corrugated steel web box girder bridge is a new type of bridge that emerged in the mid-1980 s.It replaces the concrete web in the traditional box girder structure with a corrugated steel plate,which greatly reduces the weight of the upper structure and fully uses the advantages of various materials and improves the performance of the structure.In this paper,a continuous rigid-frame bridge with corrugated steel webs and PC box was investigated and the finite element code ANSYS was used to analyze the random vibration response of the bridge under the multi-dimensional and multi-stationary seismic acceleration power spectrum excitation.The finite element model of three-span corrugated steel web PC composite box-type continuous rigid frame bridge was constructed with ANSYS.The natural frequencies of the bridge were calculated and the vibration modes were extracted for correlation analysis.As a basics of the structural response analysis.The modal combinations of the first thirty-order modes of the bridge model were generated and 50 frequency points with different frequency spacings were generated.The Hu Jixian model was used to calculate the acceleration power spectrum of the corresponding seismic ground motion as the input stimulus.With the excitation of the seismic acceleration power spectrum along the bridge direction and the horizontal direction of the bridge,the random vibration analysis was conducted by considering the irrelevance and complete correlation between the excitations.The bridge seismic response was obtained.The result shows that,when the two groups of irrelevant(or fully correlated)excitations are input along the bridge direction,the mid-span part of the bridge has the largest response at which maximum displacement is 3.53 cm when excitation is incoherent,and 4.82 cm when excitation is completely coherent.When two groups of irrelevant(or fully correlated)excitations are input along the horizontal bridge,the part from the mid-left span to the right mid-span is affected more(the maximum displacement is 3.79 cm when the excitation is irrelevant,and the maximum displacement is 4.83 cm when the excitation is completely coherent),The comparison of the calculation results shows that when the two groups were energized along the bridge,the affected area of the bridge upper structure was less than the input along the horizontal of the bridge.However,in terms of the degree of the impact,the incentive along the horizontal of the bridge was greater than when entering along the bridge.