柱面张弦桁架结构考虑行波效应的多点地震反应分析

Seismic response analysis of cylindrical truss string structure under multi-support excitation considering traveling wave effect

为了研究多遇地震下柱面张弦桁架结构多点地震反应规律,采用STCAD软件建立了9个常见尺寸的结构有限元模型,再导入SAP2000中分别进行多点和一致激励时程分析,考虑了行波效应的影响,选取了合理视波速和不同地震波传播方向。通过对比多点和一致激励时程分析结果,得到了多点激励对柱面张弦桁架结构地震响应的影响,以及多点激励效应随结构尺寸参数、地震波传播方向等因素的变化规律。结果表明:多点激励对上部桁架的影响很大,对主索和撑杆的影响一般可以忽略;上部桁架多点激励效应与结构尺寸参数存在相关性;结构形式的差异性导致地震波传播方向对上部桁架多点激励效应影响很大。根据分析结果,给出了上海地区此类柱面张弦桁架结构考虑多点激励效应后的地震作用效应调整系数。

In order to study rules of seismic response of cylindrical truss string structure under multi-support excitation for frequent earthquakes, nine common size structural finite element models were established using the software STCAD. And then time-history analyses under multi-support excitations and uniform excitations were performed respectively after importing models into software SAP2000. The influence of the traveling wave effect was considered, a reasonable apparent wave velocity and different seismic wave directions were selected. The multi-support excitation’s impact on seismic responses of cylindrical truss string structure and change rule of multi-support excitation effect with regard to structural scale parameters and seismic wave direction were obtained by comparing the results of multi-support excitation and uniform excitation time-history analyses. The results show that the multi-support excitation has a great impact on the upper truss, but the impact on cables and struts can be neglected generally. There exists correlations between upper truss multi-support excitation effect and structural scale parameters. The difference of the structure form causes the seismic wave direction to have a great influence on the multi-support excitation effect of the upper truss. According to the analysis results, the seismic action effect adjustment coefficient of this kind of cylindrical truss structure in Shanghai area is given after considering the multi-point excitation effect.