基于子集模拟的非线性相邻结构地震碰撞易损性及风险评估方法

鉴于利用线性相邻结构的相对位移峰值估计避免地震碰撞的最小结构间距的方法安全水平未知，提出基于性能的概率方法用于评估非线性相邻结构发生地震碰撞的风险. 利用高效计算小失效概率的子集模拟法对地震碰撞易损性进行计算；以动力特性差异显著的等高多自由度相邻结构为例，研究不同结构间距下考虑非线性与否的相邻结构地震碰撞易损性与风险的规律；将所提方法用于评估结构间连接减轻相邻结构地震碰撞概率的效果. 结果表明，非线性相邻结构的地震碰撞概率随地面峰值加速度的增加整体呈增大趋势，但存在局部波动；结构间距越大，考虑非线性与否所得的地震碰撞概率差别越大；当结构间距较大时，为了保证减撞效果，结构间连接刚度须足够大.

Seismic pounding fragility and risk assessment method for nonlinear adjacent structures based on subset simulation

Existing procedures to determine a minimum separation distance needed to avoid seismic pounding are based on approximations of the peak relative horizontal displacement between linear adjacent buildings, and are characterized by unknown safety levels. Thus, a performance-based probabilistic procedure for assessing risk of seismic pounding between nonlinear adjacent buildings was proposed. An efficient small failure probability method, i.e. subset simulation, was used for calculating the seismic pounding fragility of adjacent buildings. The multi-degree-of-freedom systems of equal height with substantially different dynamic properties were taken as examples to assess the rules of seismic pounding fragility and risk with and without considering nonlinear behavior of adjacent buildings at different separation distances. Moreover, the proposed method was employed to assess the performance of link elements connecting the adjacent structures, which aimed at decreasing the pounding probability. Results show that with the increase of peak ground acceleration, the seismic pounding fragility curves with considering nonlinear behavior of adjacent buildings are generally monotonic and non-decreasing but have local variations. The difference between the seismic pounding probabilities of adjacent structures with and without considering nonlinear behavior becomes larger with the increase of separation distance. When the separation distance is large, the stiffness of linking between the adjacent structures should be large enough to achieve the goal of pounding mitigation.