不同地震动作用下高耸结构的地震响应规律研究

Research on Seismic Response Law of Towering Structures in Different Ground Motion

高耸结构具有自振周期长、对低频激励敏感、抗震性能要求高等特点,为明确高耸结构在不同地震强度作用下的动力响应规律,本文以某典型高耸电视塔结构为原型,按照1:20缩尺比例设计制作了其缩尺模型。分别开展了二类场地地震动、长周期非脉冲型地震动、近断层脉冲型地震动在小震、中震条件下的一系列振动台试验。结果表明:高耸结构在地震动作用下为多阶振型参与振动;高耸结构在不同类型地震动作用下的动力响应规律大致遵循:长周期地震动 】脉冲型地震动 】二类场地震动;当脉冲型地震动的速度脉冲周期接近于原结构基本振动周期时,高耸结构的地震响应较同类型地震动更为显著;高耸建筑顶部在长周期和脉冲型地震动作用下具有显著的鞭梢效应。

Towering structure has the characteristics of long natural vibration period, sensitive to low frequency excitation and high requirements for seismic performance. In order to clarify the dynamic response rule of towering structure under different earthquake intensities, this paper takes a typical towering TV tower structure as the prototype and designs a scaling model according to 1:20 scaling scale. A series of shaking table tests were carried out under the conditions of minor and moderate earthquakes, such as ground motion of the second type, long period non-pulsed ground motion, and near-fault pulsed ground motion. The results show that the high-rise structure vibrates with multiple modes under the action of ground motion. The dynamic response law of towering structures under different types of ground motion follows roughly: long period ground motion >pulsed ground motion >secondary field vibration;when the velocity pulse period of the pulse type ground motion is close to the basic vibration period of the original structure, the seismic response of the high-rise structure is more significant than that of the same type ground motion. The top of tall buildings has significant whipping effect under long period and pulse type ground motion.