断层地震动作用对双层隔震体系倾覆特性的影响

Influence of Near-Fault Ground Motion on Overturning Characteristics of Double Layer Isolation System

为研究双层隔震体系抗倾覆性能受近断层地震动的影响,将中间隔震层分别设置在第三层、第六层和第九层,建立双层隔震体系,输入不同运动特征的近断层地震波,探讨双层隔震体系的抗倾覆性能。研究表明:近断层脉冲型地震动严重影响双层隔震体系的抗倾覆性能,随着地震动加速度峰值增加这一影响会更明显,含速度脉冲的滑冲效应和破裂向前方向效应容易使结构发生倾覆破坏。近断层地震动作用下,双层隔震体系隔震层的压应力不会超限,但隔震层位移和拉应力会超出限值导致隔震层倾覆,且双层隔震体系包含的两个隔震层中,基础隔震层倾覆风险更大;中间隔震层设置在第三层时,双层隔震体系的抗倾覆性能表现最优。

To study the impact of near fault ground motion for the anti-overturning performance of a double layer isolation system,the intermediate isolation layers are set up on the third,sixth,and ninth floors,respectively.The double layer isolation system is established,and near fault seismic waves with different motion characteristics are input to explore the anti-overturning performance of double layer isolation system.Research shows that the near-fault pulse type ground motion seriously affects the anti-overturning performance of the double layer isolation system.As the peak acceleration of the seismic motion increases,this effect becomes more pronounced.The structure is prone to overturning failure under the fling step effect containing velocity pulses and rupture forward directivity.Under the action of near fault ground motion,the compressive stress of the isolation layer of double-layer isolation system will not exceed the limit,but the displacement and tensile stress of the isolation layer will exceed the limit value,leading to the overturning of the isolation layer.Moreover,among the two isolation layers included in the double-layer isolation system,the overturning risk of the basic isolation layer is greater.When the intermediate isolation layer is set at the third floor,the anti-overturning performance of double layer isolation system is the best.