具有屈服后硬化刚度减震结构等效速度谱研究

Study on equivalent velocity spectrum of damped structure with hardening post-yielding stiffness

具有屈服后硬化刚度减震结构的输入能计算中,等效速度谱一般通过改变结构阻尼比获得,这与实际不符,而不同的反应谱对输入能的计算精度影响较大。本文旨在构建综合考虑结构参数、场地类别和地震类型的等效速度谱,为相关减震结构能量设计提供参考。基于此,首先,建立了考虑屈服后硬化刚度影响的能量平衡方程及其运动方程,并构建了具有屈服后硬化刚度单自由度(single degree of freedom,SDOF)体系等效速度谱计算程序;其次,选取了不同场地类别和地震类型的120条地震记录,利用上述程序分析了屈服后硬化刚度、阻尼比、延性系数、场地类别和地震类型等五种因素对等效速度的影响规律;最后,利用数据拟合工具提出了综合考虑多因素影响的等效速度谱计算公式并与程序计算结果对比。研究表明:等效速度随硬化刚度系数的增大呈减小趋势,但对等效速度谱的下降段影响较小,同时,等效速度随延性系数和阻尼比增大也有减小趋势,但阻尼比影响更为显著。

In the calculation of input energy of damped structure with hardening post-yielding stiffness,the equivalent velocity spectrum is generally obtained by changing the damped ratio of the structure,which is inconsistent with the actual situation,and different response spectra have great influence on the calculation accuracy of input energy.This paper aims to construct an equivalent velocity spectrum that considers structural parameters,site classifications and types of earthquake,providing reference for energy design of related damped structures.Based on this,the energy balance equation and its motion equation considering the influence of hardening post-yielding stiffness were established,and the calculation program of equivalent velocity spectrum for single degree of freedom(SDOF)system with hardening post-yielding stiffness was compiled.Then,120 seismic records of different site classifications and types of earthquake were selected,and the influences of five factors including hardening post-yielding stiffness,damped ratio,ductility coefficient,site type and earthquake type on equivalent velocity were analyzed by using the above program.Finally,the calculation formula of equivalent velocity spectrum considering multiple factors was proposed,which was obtained by using the data fitting tool,and its calculation results were compared with that of the program.The results show that the equivalent velocity decreases with the increase of the hardening post-yielding stiffness coefficient,but it has little effect on the descending section of the equivalent velocity spectrum.At the same time,the equivalent velocity also tends to decrease with the increase of ductility coefficient and damped ratio,but the effect of damped ratio is more significant.