山地掉层框架-摇摆墙结构抗震性能研究

Seismic performance of step-terrace frame-rocking wall structure

竖向刚度不均匀是山地掉层框架结构的突出特点,其在地震作用下的动力反应特性与普通框架结构存在较大的差异,山地掉层框架结构在地震中易在上接地层出现层屈服破坏机制。为改善该类结构的抗震性能,在山地掉层框架结构外部附加底部铰接、具有一定转动能力的摇摆墙,形成山地掉层框架-摇摆墙结构体系。对3个总层数为七层的掉不同层不同跨的山地掉层框架摇摆墙结构进行动力弹塑性分析结果表明,附加摇摆墙的山地掉层框架结构的基本周期较原结构的相差不大。摇摆墙设置在不同位置的山地掉层框架摇摆墙结构动力反应特性不同。摇摆墙的加入能够均匀结构各层层间变形,有效改善山地掉层框架结构的抗震性能,可避免原薄弱层上接地层的破坏集中现象,实现了整体耗能机制。

The non-uniform vertical stiffness is a prominent feature of the step-terrace frame structure. The dynamic response characteristics of the structure under seismic excitation are quite different from those of the ordinary frame structure. The failure mechanism of story yielding of the step-terrace frame structure is easy to occur at the upper ground story. In order to improve the seismic performance of this kind of structure,this paper added articulated bottom of ground floor and rocking wall with certain rotational ability to form a step-terrace frame-rocking wall structure. Three step-terrace frame-rocking wall structures with seven stories and different spans were used to carry out the numerical analysis. The results show that the basic period of the structure with additional rocking walls is not significantly different from that of the original structure. The location of the rocking wall has a great influence on the seismic performance of the step-terrace frame-rocking wall structure,and the addition of the rocking wall can uniform the deformation between the stories of the structure,effectively improve the seismic performance of the step-terrace frame structure,avoid the centralized failure of the ground story on the original weak floor,and realize the overall energy dissipation mechanism.