【摘要】 确定结构及构件的地震耗能是基于能量抗震设计的关键。根据等效单自由度体系的分析思路,将多层结构在地震作用下的能量平衡关系等效为第1阶振型SDOF体系的能量平衡关系。定义SDOF体系滞回能量除以地震峰值加速度的平方为标准化滞回能量,将SDOF体系能量平衡关系转化为标准化能量平衡关系。进而建立了等延性系数的标准化滞回能量谱理论。在此基础上提出了通过标准化滞回能量估算多层结构滞回能量的方法:(1)通过pushover分析和地震需求谱确定地震下系统的目标延性;(2)将系统的等效周期和目标延性代入等延性系数标准化滞回能量谱中确定标准化滞回能量;(3)通过标准化滞回能量值计算出多层结构的滞回能量值。通过一幢5层结构的算例分析,说明了滞回能量估算方法的操作程序,将估算结果与非线性时程分析的平均结果进行比较可知,估算结果较为准确,且偏于安全。更多还原

【Abstract】 Calculation of structural energy is the key problem for energy-based seismic design.The energy balance equations of multistory structures are equivalent to the energy equation of the first order mode of vibration of SDOF system based on the hypothesis of equivalent SDOF system.The normalized hysteretic energy is defined as the ratio of the hysteretic energy and the square of earthquake peak acceleration,and then the normalized energy balance equation is established.Therefore,the method for estimating hysteretic energy of multistory structures is presented:(1)The object ductility of the equivalent SDOF system is obtained by Pushover Analysis and seismic demand spectra;(2)The equivalent period and object ductility are substituted into the normalized hysteretic energy spectra,and the normalized hysteretic energy of the equivalent SDOF system is calculated.(3)the Hysteretic energy of a multistory structure is calculated according to the relationship between normalized energy and energy.The procedure is demonstrated by an example in which a 5-storey RC structure under earthquake motions is analyzed and 30 earthquake motion records are selected and used for energy analysis and energy spectra establishing.The example analyses show that the method proposed in the paper is easy to operate and the estimated results of hysteretic energy are more accurate and safer in hard soil site.更多还原