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加加速度是加速度关于时间的变化率,反映了结构受力变化情况。地震动加加速度及其反应谱的研究可以加强人们对地震动非平稳性的认识。阐述了加加速度的力学意义及研究价值,探讨了计算加加速度的动力学方法并对其优缺点进行了比较。建立了地震动下弹性及弹塑性加加速度反应谱的求解方法。根据场地类型、放大系数、延性系数及折减系数等影响因素对加加速度反应谱的特性进行了研究,并提出了冲击折减系数的概念。结果表明加加速度对中短周期的建筑结构作用较明显,适当提高延性将有效降低加加速度造成的冲击效应。冲击折减系数随着结构周期增大明显增大,加加速度对于长周期结构的影响一般可以忽略。
The jerk is the rate of change of acceleration with respect to time, which reflects the change of the structure’s force. Research on the acceleration and response spectrum of earthquakes can enhance people’s understanding of the non-stationarity of earthquakes. The mechanics significance and research value of jerk are expounded. The dynamic method of calculating jerk is discussed and its advantages and disadvantages are compared. The solving method of elastic response and elastic-plastic acceleration response spectrum under earthquake is established. The characteristics of jerk response spectrum are studied according to the factors such as site type, amplification factor, ductility factor and reduction factor, and the concept of impact reduction factor is proposed. The results show that the jerk effect on the short and medium-term structural effect is more obvious, and proper ductility will effectively reduce the jerk effect caused by jerk. The impact reduction coefficient increases obviously with the increase of structural period, and the influence of jerk on the long-period structure can generally be neglected.