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对底部隔震悬臂梁的地震等效作用和效应进行了研究。水平力作用下具有弯曲型侧移曲线的悬臂梁在动力特征上与高层结构接近,隔震悬臂梁可作为隔震高层结构的一种等效的简化模型。采用伯努利-欧拉梁理论推导出底部隔震悬臂梁的周期和振型,利用振型反应分解谱法分析隔震悬臂梁的地震效应,研究隔震前后各振型的等效地震作用的变化。研究发现隔震高层减振的主要原因在于调整了各振型对内力的贡献比例,延长了高阶振型的周期,从而降低高阶振型的影响,实现减振的目的;隔震对结构上部和底部作用也不同,且对剪力影响大于弯矩;隔震层刚度越弱,对高阶振型的抑制作用越明显,隔震后与隔震前1阶振型的周期比大于1.4可取得较好的隔震效果,规则的隔震高层结构可只采用2个振型计算。
The seismic equivalent effect and effect of bottom isolated cantilever are studied. The cantilever beam with curved lateral displacement curve under horizontal force is close to the high-rise structure in dynamic characteristics, and the isolated cantilever beam can be used as an equivalent simplified model of isolated high-rise structure. The Bernoulli-Euler beam theory is used to derive the period and mode shape of the bottom isolated cantilever beam. The seismic response of isolated cantilever beam is analyzed by using the modal response decomposition spectral method. The equivalent seismic effect of each mode before and after isolation The change. It is found that the main reason for the vibration isolation of high-rise isolation houses is to adjust the contribution ratio of each type of vibration to the internal force and prolong the period of high-order vibration modes so as to reduce the influence of high-order vibration modes and achieve the purpose of vibration reduction. And the impact on the shear is greater than the bending moment; the weaker the stiffness of the isolation layer, the more pronounced the inhibition effect on the high-order modes, the better the interval ratio of the first-order modes after isolation and before isolation is greater than 1.4 Earthquake effect, the rules of the isolated high-rise structure can only be calculated using two modes.