持续强震作用下RC框架结构振动台试验研究

Shaking table tests of RC frame under consecutive strong ground motion excitations

持续强震作用对结构破坏作用较强,是造成2008年汶川地震中大量房屋结构破坏的主要原因之一。为研究房屋结构在持续强震作用下的结构反应特征,设计和制作了12层RC框架结构模型,并对其开展了三次模拟地震振动台试验,研究结果表明:结构在相同地震波持续强震作用下,对这种激励波的反应强度逐渐降低,并趋于稳定;当采用其他地震波对模型结构进行激励时,结构对不同地震波的反应明显增大,结构地震反应剧烈并增长迅速。根据试验研究结果,提出结构抗震稳健性的概念,对结构抗震稳健性的机理进行了探讨,并提出了结构抗震稳健性概念性计算方法,建议加强结构的抗震稳健性研究,以提高房屋结构在持续强震作用下的安全性。

Consecutive strong motion excitations have high damage capacity and they were found to cause the massive collapse of large amount of building structures in 2008 Wenchuan earthquake. To investigate the seismic behavior of the RC frame under consecutive strong earthquake excitations, the scaled model of a 12-story RC frame was built with a scaling ratio of 1/10. Three series of shaking table tests were performed using four selected ground motions. The results show that the sensitivity of the RC frame to the same input motions reduces in the 2nd and 3rd series of tests, and the structural responses are almost the same. However, the responses increase faster once using different series of input motions. Based on these observations, a new concept namely the seismic toughness was defined and the corresponding conceptual calculation method was provided. The relevant fundamental mechanism such as the ductility and damage , and the main research tasks, application method were conceptually elaborated. It is suggested to conduct related analytical and experimental studies so that the seismic performance especially the collapse prevention capacity of the structures can be improved under the consecutive strong earthquake excitations.