超长大跨结构考虑地震输入空间变化效应的响应特征

Seismic Response Characteristic of Long-Span Structures Considering Earthquake Input Spatial Variability Effects

基于多点随机地震动场模型推导了包含三向正交地震动分量联合输入的多维多点随机地震动场模型,并将虚拟激励法推广应用于考虑行波效应、部分相干效应和局部场地效应联合作用的情况,推导了相应的计算公式;系统分析了考虑地震输入空间变化效应时超长网壳的响应特征.结果表明,地震地面运动的空间变化效应对结构的响应有着较明显的影响.同时,计算还表明虚拟激励法对于分析大跨结构在多维多点输入下的地震响应是一种高效且精确的方法.

According to multi-support stochastic earthquake ground motion model, a three-dimensional earthquake and multi-support stochastic earthquake ground motion model was established. Then based on the pseudo excitation method （PEM）, a random vibration methodology was formulated for the seismic analysis of multi-supported structures subjected to spatially varying ground motions. The ground motion spatial variability consisted of traveling-wave effect, incoherence effect and local site effect. The seismic response of a super long latticed roof was analyzed in detail. It shows that all these effects have significant influence on the seismic response of the structure. On the other hand, it shows the pseudo excitation method is efficient and precise and is applicable to the random seismic response analysis of the long-span structure under multi-dimensional and multi-support excitation.