拟合加密控制点反应谱的地震动时程合成

摘要

Based on traditional frequency-domain response-spectrum-compatible method of ground motion,this paper proposes a synthesized method that cangenerate ground motion which is compatible with the target response spectrum with densified controlling points,and further compares the method with the classical one compatible with target response spectra of ground motion.This method takes into account the simulation of the acceleration envelope of the ground motion during each iteration adjustment for the initial non-stationary artificial ground motions generated by the trigonometric series superposition method,and the resulting ground-motion acceleration after the each iteration will undergo the baseline correction.Therefore,the synthesized ground motion generated by the proposed method can not only match the densified target spectrum with certain precision,but also satisfy the requirement of the envelope function of acceleration time history,and the integrated displacement curve does not present any baseline drift.Numerical results show that this method can not only match the target spectrum with relatively high convergence speed,but also fit the target envelope function with high precision.In addition,this method can realize baseline correction for the initial ground motion.%在传统地震动反应谱频域拟合方法的基础上,提出了拟合加密控制点目标反应谱的地震动合成方法,并在此基础上利用实际算例与传统方法进行了对比.本文方法在每次迭代调整过程中均考虑了对地震动加速度强度包络函数的模拟,并且对调整后的地震动进行了基线校正,从而确保最终合成的地震动时程既能以一定精度拟合加密目标反应谱,又能满足目标包络函数的要求,同时保证积分所得位移曲线不产生基线漂移.数值算例分析结果表明,本文方法与传统非加密控制点目标谱拟合方法相比,在地震动时程曲线合成、反应谱拟合精度以及收敛速度等方面均具有一定的优势.