SSI效应对粘弹性阻尼结构减震效果的影响分析

本文以一单跨7层框架结构为研究对象，对不同场地和地震波输入条件下的粘弹性阻尼结构进行了二维有限元时程分析，探讨了SSI（土-结构动力相互作用）效应对粘弹性阻尼结构减震效果的影响。分析结果表明：①在硬土和稍硬土地基条件下，SSI效应明显降低了结构的楼层位移峰值，若在抗震设计中对客观存在的SSI效应加以考虑，设置较少数量的阻尼器（与刚性地基假定条件下确定的阻尼器数量相比）就能使结构的实际地震位移反应满足基于刚性地基假定的地震位移控制目标；②粘弹性阻尼结构的减震效果与场地条件、输入地震动特性密切相关；③与刚性地基相比，SSI效应使粘弹性阻尼结构的减震效果明显降低，且地基越软，降低幅度越大。因此，在实际的工程设计中，应当充分考虑SSI效应，对粘弹性阻尼结构的减震控制效果进行合理的评价，并针对不同的场地条件选用合适的阻尼器类型和性能参数，才有可能达到预期的减震控制效果。

Analysis of Influence of SSI Effects on Controlling Efficiency of Viscoelastic Structures

The dynamic responses of a single-span, seven-storey frame on several construction sites were computed with the 2D finite element method for a few records of seismic waves to analyze the influence of SSI effects on the controlling efficiency of viscoelastic structures. The analyzed results indicate： （1）on sites of hard or slightly hard soils ,the SSI effects clearly reduce the peak values of storey displacement so that, to make the actual displacement response of a structure satisfy the aseismic control objective based on the assumption of rigid ground, relatively few viscoelastic dampers are needed （compared with the number of viscoelastic dampers needed under the assumption of rigid ground） if the SSI effects are considered in the aseismic design; （2）the controlling efficiency of the viscoelastic dampers is closely related to the construction sites and the seismic waves; （3）compared with the rigid ground, the SSI effects reduce greatly the controlling efficiency of the viscoelastic dampers; and the softer the soils, the more the controlling efficien- cy will be reduced. Therefore, in real engineering designs, the SSI effectd should be taken into account to evaluate properly the controlling efficiency of the viscoelastic dampers. At the same time, the right type of dampers should be selected according to the site condition so that the prospective control objective can be achieved.