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基于HHT变换得到瞬时能量谱,并以简谐地震反应为理论基础进行多自由度体系在地震动作用下的瞬态反应计算。通过对一个长周期(十五层)结构工程实例的地震瞬态反应计算分析,揭示长周期结构有别于短周期结构动力响应的独特特性:长周期结构位移响应的瞬时能量峰值的时间滞后于地震动能量峰值的时间,且主要受到瞬态振动的控制,并以低阶振型的控制为主,第一阶振型峰值位移滞后的时间最长,滞后的时间主要取决于结构的第一阶自振周期。研究结果表明,长周期结构在强烈地震动作用下,地震动强度出现的最大时刻并不总是对应于结构破环与倒塌的时间。
Based on the HHT transform, the instantaneous energy spectrum is obtained, and the transient response of the multi-degree-of-freedom system under the action of the earthquake is calculated based on the simple harmonic seismic response theory. The transient response analysis of a long-period (fifteen-story) structural engineering project reveals the unique characteristics of long-period structures that are different from the dynamic response of short-period structures: the time lag of transient energy peaks of the long-period structure displacement response The time of peak energy of earthquake is mainly controlled by the transient vibration and dominated by the low-order mode. The peak of the first-order mode has the longest delay and the lag time is mainly determined by the first Free vibration cycle. The results show that the maximum moment of earthquake intensity does not always correspond to the time of structural failure and collapse under the action of strong earthquake.