长周期地震动作用下基础隔震结构抗倾覆能力研究  

Study on the overturning resistance of base-isolated structure under the action of long-period ground motion

作　　者：张亮泉[1] 夏天 ZHANG Liangquan;XIA Tian(School of Civil Engineering,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]东北林业大学土木工程学院,黑龙江哈尔滨150040

出　　处：《自然灾害学报》2023年第4期170-180,共11页Journal of Natural Disasters

基　　金：国家自然科学基金项目(52178513)。

摘　　要：对极限高宽比的基础隔震结构进行地震响应分析,探究常规地震动与长周期地震动的差异,并从隔震层位移、隔震层拉应力以及结构的抗倾覆力矩比3种导致结构倾覆的参数入手,分析基础隔震结构在长周期地震动作用下的倾覆情况。首先,选取近断层脉冲型长周期地震动和远场类简谐长周期地震动各9条。其次,建立3种不同烈度区下极限高宽比限值时的框架隔震结构模型,分析不同设防烈度下罕遇地震对基础隔震结构隔震层支座水平变位与轴向受力的影响,以及罕遇地震时结构的抗倾覆力矩比。最后,修正高宽比限值简化公式,计算出长周期地震动作用下的理论高宽比限值,根据限值修正结构高宽比后再进行地震响应分析。研究结果表明:在长周期罕遇地震动作用下,基础隔震结构隔震支座位移量普遍超过允许限值,大量支座出现拉应力,其中部分支座拉应力超过允许限值,隔震层受到严重破坏;少数情况下结构抗倾覆比小于1.2,结构有倾覆可能;结合简化公式给出长周期地震动作用下高宽比建议值。In this paper,the seismic response analysis of base-isolated structures with ultimate aspect ratio is carried out to investigate the difference between conventional ground motion and long-period ground motion,and the overturning of base-isolated structures under long-period ground motion is analyzed from the perspective of three parameters leading to structural overturning,namely,isolation displacement,isolation tensile stress,and the overturning moment ratio of the structure.Firstly,nine near-fault impulsive long-period ground motion and nine far-field simple harmonic long-period ground motion are selected.Secondly,the frame seismic isolation structure models are established for three different intensity zones at the limiting height-to-width ratio limits,and the effects of rare earthquakes on the horizontal displacements and axial stresses in the isolation layer of the base isolation structure,as well as the moment ratio of the structure to resist overturning in the case of the rare earthquakes,are analyzed.Finally,the simplified formula of the aspect ratio limit is modified to calculate the theoretical aspect ratio limit under the action of long-period ground motion,and the seismic response analysis is carried out after the structural aspect ratio is modified according to the limit.The results show that,under the action of long-period rare faction ground motion,the displacements of isolation bearings of the base isolation structure generally exceed the permissible limit,and a large number of bearings have tensile stresses,some of which exceed the permissible limit,and the seismic isolation layer is seriously damaged.In a few cases,the structural tilt resistance ratio is less than 1.2,and there is a possibility of structural overturning.Further more,a suggested value of the aspect ratio is given by combining with the simplified formula for the action of long-period ground motion.

关 键 词：高宽比 长周期地震动 基础隔震结构 抗倾覆能力 

分 类 号：P315.9[天文地球—地震学]