基于弹塑性限位装置的基础隔震建筑地震碰撞行为

在近场速度脉冲型地震作用下，基础隔震建筑可能产生过大的支座变形，为了防止结构和隔震沟边缘产生刚性碰撞并对上部结构造成损伤，建议在隔震层高度用弹塑性限位装置来防止结构产生过大位移并实现一定程度的消能减震。提出了一组动力学方程，将建筑结构模型和Bouc-Wen单元串联，可以考虑隔震间隙的非线性动力响应。考虑了速度脉冲周期对结构响应的放大作用，根据弹塑性动力碰撞分析方程，以3组不同高度的钢框架结构基准模型为算例，计算了限位装置的弹性刚度和屈服力等因素对不同结构的弹塑性响应。结果表明：恰当选取用于碰撞限位的弹塑性限位装置的碰撞刚度与屈服力，既能有效限制隔震层的水平位移，上部结构也不会产生过大的反向动力响应，能够充分保护结构；在较易激发类共振效应的速度脉冲型地震动作用下，上部结构最大响应同弹塑性限位装置的弹性刚度与屈服力呈正相关性。

Collision behaviors of base-isolation structures with elastoplastic horizontal displacement stopper

Under the near-fault velocity pulse-like ground motions, the base-isolation building structures may produce excessive bearing deformation. To prevent the damage caused by the hard collision between the building isolated layer and the edge of the isolation trench, an elastoplastic horizontal displacement stopper was proposed in this paper, which was placed at the base isolation altitude to limit the excessive displacement of buildings and absorb the seismic energy to some extent. A set of kinematical equations combining the structural model and Bouc-Wen model were presented, which consider the nonlinear dynamic effects of isolation gap. The amplification effects caused by the similarity between the period of velocity pulse-like vibration and the building fundamental period were considered. Base on analysis of governing equations of motions with collision against the stopper, the influence of elastic stiffness and yielding force of stopper on the ultimate response of superstructure was investigated based on three benchmark models of steel frame buildings. The results show that a selection of appropriate yield force and impact stiffness for isolation stopper would be beneficial for limiting the horizontal displacement of isolated layer as well as avoiding the damage of the superstructure of building caused by excessive reverse movement. Under the influence of near-fault pulse-like ground motion, the maximum dynamic response of superstructure exhibits a significant correlation with the yield force and elastic stiffness of stopper.