基于经验相干损失函数和《建筑抗震设计规范》定义的反应谱模拟了空间变化地震动,进行了空间变化水平向和竖向地震动共同激励下桁架拱结构的反应分析。数值分析结果表明,与一致激励引起的结构反应相比,考虑地震动的空间变化增大了桁架拱结构的地震反应,引起地震动空间变化的每一个因素对于结构反应都有重要的影响。传统的基于一致地震动和仅考虑行波效应空间地震动的抗震分析可能低估大跨度结构的地震反应。数值结果同样表明,与仅考虑地震动水平向激励相比,同时考虑地震动水平向激励和竖向激励能够更准确地评估大跨度桁架拱结构的地震反应。
The spatially varying ground motions were simulated based on an empirical coherency loss function and the response spectrum defined in Chinese seismic design code. Intensive numerical calculations of the responses of the trussed arch subjected to the combined spatially varying horizontal and vertical ground motion excitations were carried out. Compared with structural responses calculated using uniform excitations, numerical results have highlighted that seismic response is amplified when considering ground motion spatial variations. Each factor of ground motion spatial variations has a significant effect on the dynamic response of the structure. The conventional seismic analysis with uniform ground motion assumption or with spatial variations considering wave passage effect only may underestimate the seismic response of long span structure. Numerical results also indicate that considering simultaneous vertical and horizontal ground motions will lead to more accurate response predictions of the trussed arch as compared with those obtained by considering horizontal excitations only.