摘要
提出一种改进的基于小波函数的地震动反应谱拟合方法,该方法通过调整给定地震动加速度时程,使其反应谱以一定精度拟合目标谱。首先,构造一种用于校正的增量加速度小波函数,该函数具有两个特点:①在反应谱的某个固定控制周期点处,对该函数进行时移和线性调幅处理后,将其叠加在初始地震动时程上,所得地震动时程在该控制周期点处的反应谱值与目标值精确相等;②由该函数积分得到的增量速度和增量位移曲线不出现基线漂移,从而保证将其叠加在初始地震动上不会产生附加的基线漂移。其次,基于该小波函数,提出迭代调整方法,以消除反应谱不同控制周期点之间的耦合效应,实现对整个目标谱的拟合。数值算例表明,该方法合成的地震动时程不仅能够以较高的精度拟合目标谱,而且能够保留初始天然地震动的基本特征,从而能够确保结构地震反应分析结果的合理性与可靠性。此外,该方法具有较快的收敛速度,能够通过有限几步迭代调整实现较高的拟合精度。
Abstract： An improved wavelet-based spectral matching method is proposed to modify given ground motion to make its response spectrum match the target spectrum more precisely. An incremental acceleration wavelet function is constructed with following two properties： ① at some controlling period of response spectrum, after being time-shifted and linear-scaled, the wavelet can be superimposed onto the initial ground motion to generate a new one whose spectrum is equal to the target value at this controlling period; ② the incremental velocity and displacement obtained by integrating the wavelet do not exhibit baseline drift, thus there is no additional baseline drift when superimposing it onto the initial ground motion. Based on the wavelet, an iterative modification method is proposed to eliminate the coupling effects among different controlling periods of response spectrum to realize the matching of whole target spectrum. Numerical results show that the ground motion synthesized by the method can not only match the target spectrum with relatively high precision, but also retain the basic features of original natural ground motion, so the rationality and reliability of analysis of structural dynamic responses can be ensured. In addition, the proposed method can realize high matching precision with limited iterations.
出处
《土木工程学报》
EI
CSCD
北大核心
2014年第1期70-81,共12页
China Civil Engineering Journal
基金
北京市自然科学基金(8112029)
国家自然科学基金(51178436)
国家科技重大专项(2011ZX06002-010)
关键词
抗震设计
结构地震反应
反应谱
时程分析
地震动合成
aseismic design
structural dynamic response
response spectrum
time-history analysis
ground-motion synthesis
