弹性能量半径演化谱及其在多自由度体系地震反应计算中的应用

目前用于结构抗震设计的反应谱仅能反映峰值反应,无法体现反应值随时间的变化。文中提出一种弹性能量半径演化谱,可反映线性单自由度体系弹性能量(即动能与弹性势能之和)随地震持时的变化,且其峰值近似等于结构峰值位移。文中给出了利用地震动演化功率谱得到该演化谱的方法并进一步发展了一种计算线性多自由度体系地震位移反应的新方法。通过两座框架结构的地震反应计算,将新方法与传统振型组合法及时程分析法的计算结果进行对比,发现对于振型稀疏结构,新方法计算结果与SRSS法接近;而对于振型密集结构,新方法计算结果较CQC法更精确,且避免了CQC法相关系数的复杂计算。

Elastic energy radius evolutionary spectra and application to calculate MDOF structure seismic response

At present,the response spectra used in structural seismic design can only reflect the peak response,but can not reflect the change of response along with time.In this paper,elastic energy radius evolutionary spectra(EERES)is raised to descirbe change of structure elastic energy(in other words,kinetic energy and elastic potential energy)along with seismic duration.EERES,whose peak value is approximately equal to peak seismic displacement,can be obtained by evolution power spectrum of ground motion and used to calculate seismic response of MDOF system.Then two frame structures'seismic displacement response is calculated by EERES,mode-superposition or dynamic time history analysis method.It shows that result by EERES is more accurate than which by CQC if structure modes are close.While the results by EERES and SRSS are simliar if structure's modes are loose.