This paper presents the main results of an investigation focused on evaluating the height-wise distribution and amplitude of permanent interstorey drift, RIDR, demands of four case-study steel moment-resisting frames subjected to near-fault earthquake ground motions having forward-directivity effects (NF-FD) with increasing seismic intensity. To provide a context, maximum (transient) interstorey drift, IDR, demands were also computed as part of this study. Examining the results from nonlinear time-history analyses revealed that the case-study building models exhibited a recentering behaviour under NF-FD earthquake records, which means that the amplitude of RIDR at specific stories decreases with respect to the amplitude reached at a lower ground motion intensity. Scatter plots of maximum RIDR and IDR demands, and vice versa, revealed that both response parameters follow a nonlinear trend, which it can be approximated by a power funtion. Additionally, the ability of two velocity pulse analytical models introduced in the literature to estimate RIDR demands was also examined in this investigation. It was observed that both velocity pulse models lead to a different amplitude of RIDR demands computed from recorded earthquake ground motions; however, those equivalent pulses are adequate for estimating IDR drift demands as noted in previous studies.

本文介绍了一项主要研究结果，重点是评估永久性层间漂移RIDR的高度分布和振幅，这四个案例研究的抗矩钢框架承受了具有前向效应的近断层地震地震动的要求（NF-FD）随着地震强度的增加。为了提供一个背景，最大（瞬时）层间漂移IDR需求也作为该研究的一部分进行了计算。检查从非线性时程分析的结果表明，案例研究建立模型展现的一个recentering下NF-FD地震记录的行为，这意味着振幅RIDR相对于在较低地面运动强度下达到的振幅，在特定情况下的减小。最大RIDR和IDR需求的散点图（反之亦然）表明，两个响应参数均遵循非线性趋势，可以通过功率函数对其进行近似。此外，本研究还检查了文献中介绍的两种速度脉冲分析模型估计RIDR需求的能力。观察到，两种速度脉冲模型都导致根据记录的地震地面运动计算出的RIDR需求幅度不同；但是，这些等效脉冲足以估算IDR 如先前研究中所述的漂移需求。