Smooth Acceleration Spectra for Pulse-Like Ground Motions
Smooth Acceleration Spectra for Pulse-Like Ground Motions
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DOI：
10.1785/0120200137
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发表时间：
2020-12
影响因子：
3
通讯作者：
Cuihua Li;Guofeng Xue;Zhanxuan Zuo
中科院分区：
文献类型：
--
作者：
Cuihua Li;Guofeng Xue;Zhanxuan Zuo
加速度反应谱的理想化是构造结构抗震设计和评估目标谱的基础。本文研究了现有方法合理理想化(或平滑)脉冲型和非脉冲型地震动加速度谱的充分性。首先利用小波变换研究了分离脉冲对加速度反应谱不同区域的影响。选取一种具有代表性的方法作为基准，考察了基于Newmark-Hall方法平滑脉冲型和非脉冲型地面运动的加速度谱的有效性。对于为什么基于Newmark-Hall的方法可能低估与恒加速度分支相关的平台(或放大系数)而高估结束截止期Tg，提出了一些重要的见解。这项研究强调了恒加速度分支的内在特性和重要性，并在此基础上提出了一种两步法来理想化加速度谱。结果表明，无论脉冲对加速度谱下降分支的影响如何，该方法都能准确地识别出恒加速度分支。
Idealization of acceleration response spectra is the basis for construction of target spectra for seismic design and assessment of structures. The adequacy of current methods to reasonably idealize (or smooth) the acceleration spectra of pulse-like and nonpulse-like ground motions is examined in this study. The influence of separated pulses on different regions of acceleration response spectrum is first investigated using wavelet transform. One representative method is selected as the benchmark to examine the effectiveness of the Newmark–Hall-based methods to smooth the acceleration spectra of pulse-like and nonpulse-like ground motions. Presented are some important insights into why the plateau (or amplification factor) associated with the constant-acceleration branch may be underestimated and the ending cutoff period Tg be overestimated by Newmark–Hall-based methods. This study highlights the intrinsic characteristics and the importance of the constant-acceleration branch, based on which a two-step procedure is proposed to idealize the acceleration spectra. The results show that the proposed methodology can accurately identify the constant-acceleration branch regardless of the influence of pulses on the descending branch of acceleration spectra.