近场地震下竖向刚度不同的混合结构动力性能分析

近场地震的动力特性明显不同于远场地震,因此有必要对结构在近场地震作用下的动力性能展开研究。以上部钢结构-下部混凝土结构这类竖向刚度不同的加层混合结构为研究对象,对其在近场脉冲型地震、近场无脉冲型地震及远场地震作用下的动力响应进行研究。结果表明:在多遇、设防、罕遇地震作用下,近场脉冲型地震会使结构的层间位移角、层间剪力、加速度等动力响应均放大并出现超限的情况,而且都比罕遇地震作用下结构的响应增大更明显;在进行近场区加层混合框架结构的设计和建设时,近场脉冲效应会使结构存在不满足规范的情况,有必要对竖向刚度不同的加层混合结构在近场区的适用性进行深入研究。

Dynamic Performance Analysis of Hybrid Structures with Different Vertical Stiffnesses under Near-field Earthquakes

The dynamic characteristics of near-field earthquakes are different from those of far-field earthquakes; therefore, it is necessary to analyze the seismic performance of structures under near-field ground motion in actual projects. In this paper, a hybrid structure with different vertical stiffnesses of the upper steel structure-lower concrete structure is taken as the research object. The dynamic responses of the structure under the action of near-field pulse-like ground motions, near-field non-pulse-like ground motion, and far-field ground motion are respectively studied. The results show that the near-field pulse-like earthquake will amplify the dynamic response of the story drift ration, interlayer shear force, and acceleration under frequent, designed, and rare earthquakes. Under the rare earthquake, the structural response increases the most. Because the near-field impulse effect will bring unsafe factors to the structure, it is necessary to study the applicability of the hybrid structure with different vertical stiffnesses in the design and construction of layered hybrid frame structures in near fields.