地震动在传播过程中,由于行波效应、相干效应、局部场地效应和衰减效应的存在,导致结构不同支座接收到的地震动具有空间变化性。为研究行波效应、相干效应及二者耦合效应对单层球面网壳结构地震响应的影响,集成现有较优的地震动模型,模拟空间相关非平稳地震动场,采用时程分析法,计算90m K8单层球面网壳结构在不同效应地震动场作用下的结构响应,并与一致输入下的结构响应进行比较分析。结果表明:行波效应对结构地震响应的影响随视波速增大而逐渐减小,当视波速较小时,行波效应的影响会超过相干效应,二者耦合效应的影响大于任一单一效应,同时考虑行波效应和相干效应的地震动场是较为合适的地震动输入。
Ground motions arriving at different supports of a structure are spatially varying because the wave-passage effect, incoherence effect, site-response effect and attenuation effect in the seismic propagation. Based on an excellent ground motion simulation model, spatial correlated and non-stationary seismic ground motions were simulated respectively, considering the incoherence effect, wave-passage effect and their coupling effect. Under these ground motion inputs, the seismic response of a 90m-span K8 single-layer reticulated shell under multiple support excitations were studied, considering different effects, by the method of time history analysis, and a comparison with the ones under simple support excitations was also made. The results show that the influence of wave-passage effect on the structural response depends on the traveling wave velocities, and the greater the traveling wave velocity is, the lesser the influence is. When the traveling wave velocity is low, wave-passage effect has a greater influence than that of an incoherence effect. And the influence of the coupling effect is greater than the one of either effect, thus the ground motion excitation simultaneously considering incoherence effect and wave-passage effect is relatively appropriate.