考虑屈服位移的竖向不规则结构抗震性能评估

本文给出了一种改进的模态pushover方法,对竖向不规则结构进行抗震性能评估。通过考虑不规则结构高振型的影响,利用模态pushover方法将结构简化为不同的等效单自由度体系,并对其进行弹塑性时程分析,将所得到的结果进行组合,得到原结构的楼层位移和层间位移等性能指标。由于结构处于屈服阶段与处于弹性阶段时的各节点变形的关系有显著区别,因此对于进入塑性阶段的振型,采用屈服后的各节点变形关系计算位移变形响应,将计算得到的各个振型结果组合得到整体结构的位移。通过四个算例分析,表明改进的方法所得到的结果更加接近于弹塑性时程分析的结果,证明此方法能够有效地应用于竖向不规则结构的抗震性能评估与计算。

Seismic performance evaluation of vertically irregular structure considering yield displacement

An improved modal pushover method was adopted to evaluate the seismic performance of the vertically ir-regular structures. The structures were simplified to different equivalent single-degree-of-freedom systems by modal pushover method, and the systems were calculated by the elasto-plastic time-history analysis. Then the results were combined to get the floor displacements and drifts of the original structures. As the relationships of floor deformations in the post-yield stage and the elastic stage were obviously different, the displacements were calculated depending on the relationships among the various nodes of the post-yield deformation and were combined to get the original structure displacements. Using these methods, four vertically irregular structures were analyzed. The results from the improved methods are more close to the results computed by the elasto-plastic time-history analysis. This demonstrates that the improved method could be used in the seismic performance calculation of the vertically irregular structure effectively.