Abstract In this research study, a new set of restoring force equations are proposed for seismic isolated structures subjected to far fault ground motions (FFGM) and near fault ground motions (NFGM). For this purpose, 110 FFGM and 49 NFGM are selected. Then, nonlinear time history analyses (NLTHA) of SDOF seismic isolated structures are performed using the selected ground motions to obtain their residual and maximum displacements. The analyses are repeated for an extensive range of parameters including peak ground acceleration, Ap, characteristic strength, Qd and post elastic period, Td, of the isolation system. Next, the variations of the residual and maximum displacements are plotted as functions of the various combinations of the parameters considered in the analyses. Then, nonlinear regression analyses are performed to formulate the residual and maximum displacements as functions of the parameters considered in the analyses. The developed equations are then used to formulate the upper limits of Td (restoring force equations) to ensure reasonable levels of residual and maximum isolator displacements. The developed restoring force equations are then compared with those of AASHTO and Eurocode-8 (EC-8) using the pool of residual and maximum displacement data obtained from NLTHA. It is observed that using the restoring force equations of AASHTO and EC-8 to check the design of seismic-isolated structures may, in some cases, produce unreasonably large levels of residual and maximum displacements. However, when the restoring force requirements proposed in this research study are applied, the residual and maximum displacements are observed to be within reasonable ranges.

中文翻译：

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建议的隔震结构的最小恢复力要求

摘要 在本研究中，针对受远断层地震动（FFGM）和近断层地震动（NFGM）影响的隔震结构，提出了一套新的恢复力方程。为此，选择了 110 FFGM 和 49 NFGM。然后，使用选定的地震动对单自由度地震隔离结构进行非线性时程分析 (NLTHA)，以获得它们的残余位移和最大位移。对广泛范围的参数重复分析，包括隔离系统的峰值地面加速度 Ap、特征强度 Qd 和弹性后周期 Td。接下来，将残余位移和最大位移的变化绘制为分析中考虑的各种参数组合的函数。然后，执行非线性回归分析以将残余位移和最大位移公式化为分析中考虑的参数的函数。然后使用开发的方程来制定 Td（恢复力方程）的上限，以确保剩余和最大隔离器位移的合理水平。然后使用从 NLTHA 获得的残余和最大位移数据池，将开发的恢复力方程与 AASHTO 和 Eurocode-8 (EC-8) 的方程进行比较。据观察，在某些情况下，使用 AASHTO 和 EC-8 的恢复力方程来检查隔震结构的设计可能会产生不合理的大水平残余位移和最大位移。然而，当应用本研究中提出的恢复力要求时，