近远场地震动对单自由度体系滞回耗能需求影响研究

Effect of near-fault and far-fault ground motion on the hysteretic energy demand of single degree of freedom structural system

为研究地震荷载作用下弹塑性单自由度体系的滞回耗能需求,分别输入多条不同的近远场地震动记录,进行单自由度体系的滞回耗能时程分析,对比分析发现远近场地震动记录下单自由度体系的滞回耗能需求存在明显差异,近场地震动对体系滞回耗能需求要求更高。提出了单自由度体系的滞回耗能速度谱的概念,并分别从地震动特性和结构自身特性两方面分析不同参数对滞回耗能速度谱的影响。研究表明,近远场、地震动的强度、场地条件对体系的滞回耗能需求有明显影响,单自由度体系的阻尼比对滞回耗能速度谱有明显影响。研究结果为更好地在结构设计中考虑地震动特性及实现基于能量的结构抗震设计思想提供了依据。

In order to study the hysteretic energy dissipation requirement of elasto-plastic single-degree-of-freedom(SDOF) system under seismic loads,a number of different near-field and far-field seismic records are inputted respectively,the hysteretic energy dissipation time history analysis of SDOF system is carried out.It can be seen that there is a significant difference in the hysteretic energy demand of the SDOF system under near-fault and far-fault ground motions,which means the hysteretic energy demand of the near-field ground motion is higher than others'.The concept of hysteretic energy dissipation velocity spectrum of SDOF system is proposed,and the influence of different parameters on hysteresis energy dissipation velocity spectrum is analyzed from the aspects of ground motion characteristics and structure self characteristics.The results show that it is a significant effect on the hysteretic energy dissipation of the system by the intensity,site condition and fault distance of the ground motion.The damping ratio of the SDOF system has a significant effect on the hysteretic energy dissipation rate.The results show that a basis for better considering the characteristics of ground motion in structural design and implementing energy-based structural seismic design is provided.