近断层脉冲型随机地震动模拟方法及结构动力可靠度研究

Simulation method of pulsed stochastic ground motion of near-fault and study of structural dynamic reliability

以集集脉冲型地震动记录为数据集建立了一种改进的参数化近断层脉冲型随机地震动模型.首先,采用MP03模型和人工蜂群算法从实际地震动记录提取低频脉冲部分,建立随机低频脉冲模型;采用谱表示-随机函数法生成高频部分,二者叠加生成近断层脉冲型随机地震动.然后,采用蒙特卡罗模拟(MCS)法和直接概率积分法(DPIM)分别研究非线性单自由度体系和高层框架结构在不同类型地震动作用下的动力可靠度.结果表明:DPIM与MCS法计算结果相比基本吻合,但计算效率得到较大提升,可以很好地用于非线性结构的时变可靠度研究;脉冲型地震动与非脉冲型地震动相比能够对结构造成更大的变形,极大降低了结构的可靠度,且近断层距越小影响越显著,低频脉冲是使结构可靠度降低的主要因素,而高频部分对结构可靠度的影响较小.

An improved parametric near-fault pulsed stochastic ground motion model is established using Chi Chi pulsed ground motion records as the dataset.Firstly,the low-frequency pulse part is extracted by using MP03 model and artificial bee colony algorithm from the actual ground motion records to establish a stochastic low-frequency pulse model,and then the high-frequency part is generated using the spectral representation-random function method,and the two parts are superimposed to generate the near-fault pulsed stochastic ground motion.Then,Monte Carlo simulation(MCS)method and direct probability integration method(DPIM)are used to study the dynamic reliability of nonlinear single-degree-of-freedom system and high-rise frame structure under the action of different types of ground motions,respectively.The results show that the calculation results of DPIM and MCS method basically match,but the calculation efficiency is greatly improved,which can be well used for the study of time-varying reliability of nonlinear structures;pulsed ground motion can cause greater deformation to the structure compared with non-pulsed ground motion,which greatly reduces the reliability of the structure,and the smaller the near-fault distance is,the more significant the effect is;low-frequency pulses are the main factors to reduce the reliability of the structure,while high-frequency parts have less influence on the reliability of the structure.