地震传播至结构场地时会存在空间上的变化,考虑地震空间变化性的多点输入比一致输入更符合实际.为研究地震空间变化性对单层球壳反应的影响,以行波效应为例建立地震动场,对单层球面网壳结构进行了地震多点输入与一致输入时程响应分析,分析了地震视波速、PGA和结构跨度三个因素对单层球面网壳结构地震空间相关性效应的影响程度.系统分析结果表明:地震空间变化性对结构的影响程度与结构和地震两方面因素密切相关,是否考虑地震空间变化性须由这两方面因素综合确定,当地震动场视波速较小、PGA较大时,较大跨度结构受地震空间变化性影响较大.
Ground motion varies spatially after long distance propagation to the structural site. So multiple- support excitations considering spatial correlation is more practical than simple support excitation. The time-history response of single-layer reticulated domes under multiple-support excitations and simple support excitation was analyzed. Taking the wave-passage effect as an example, the influence of ground motion on seismic spatial correlation effect for the structures with different apparent wave velocity, PGA, spans were discussed. The results after systematical analysis indicate that the influence of seismic spatial correlation effect on the structures closely relates to the structures and ground motion, which jointly determine whether spatial correlation should be considered. When the apparent wave velocity is relatively small and PGA is relatively large, seismic spatial correlation has a larger impact on large span structures.