Earthquake Response Analysis And Aagility Analysis Of Long-span Steel Structure Truss Considering Seismic Input Direction

Large-span space truss is one of the common building forms at present.Because of its good aseismic performance and various forms,spacetruss has been developed rapidly.But such buildings tend to gather a large number of people,once the earthquake will cause a large number of casualties and property losses.In the study of seismic behavior of space truss structures,it is usually assumed that the direction of earthquake action on the structure is axial,but the direction of actual earthquake action on the structure is arbitrary,and the most unfavorable angle of earthquake input is often inconsistent with the axial direction of the structure.Therefore,it is necessary to analyze the seismic behavior of space truss structures under different seismic input angles.The main contents of this paper are as follows:(1)Taking the coal storage shed in Datong,Shanxi Province as an example,the nonlinear time history analysis of the large-span space truss structure is carried out,and the peak response of the members is taken as the criterion to judge,the difference of seismic response of long-span space truss structures under different seismic input angles and the influence of different seismic waves on the most unfavorable input angles of space truss structures are studied.The results show that the seismic input angle has obvious effects on the displacement of joints,the axial force of members and the torsion effect,the most unfavorable seismic input angle is related to the type of seismic wave.(2)Selecting the seismic response combination method(SRSS,100/30,100/40)suggested by relevant codes at home and abroad to calculate the seismic response value of grid structure,the maximum seismic response of space truss structures under different seismic input angles is calculated by nonlinear time history analysis method,and the results of the two methods are compared to evaluate the safety of the three seismic response combination methods.The results show that the seismic response combinations calculated by SRSS,100/40,/100/30 seismic response combination method all exceed the structural seismic response values under the most unfavorable input angle,for the convenience of calculation,all three methods can be used,and the100/40 combination method is preferred.(3)Based on the incremental dynamic analysis(IDA),the seismic vulnerability of long-span steel grid structures is analyzed,and the ground peak acceleration(PGA)is taken as the seismic intensity index,the damage index of Space Truss structure is defined by the maximum node displacement and the elastic limit displacement.The seismic vulnerability curves of 0 °,30 ° and 60 ° structures are obtained by changing the seismic input angle,and the influence of the seismic input angle on the seismic vulnerability probability of grid structures is analyzed.Finally,the Collapse Margin Ratio(CMR)is introduced to evaluate the anti-collapse safety reserve under different earthquake input angles.The results show that the failure probability of grid structure will be underestimated without considering the seismic input angle,and the seismic response is 0 ° The collapse resistance of the grid structure is the highest when input,60 ° Next,30 ° The lowest.