聊城光岳楼动力特性及地震响应分析

Dynamic characteristics and seismic response analysis of Guangyue Tower in Liaocheng City

光岳楼位于山东省聊城市古城中央,始建于1374年,为国家重点文物保护单位。对光岳楼进行了数值模拟,建立了光岳楼上部木结构、木结构-高台基、木结构-高台基-土体结构的有限元模型,通过模态分析得出光岳楼3种模型的前8阶自振频率与振型。在分析地震响应时,选取兰州波进行地震响应分析,分别按照多遇地震和罕遇地震调整其幅值分别为55 Gal和310 Gal,输入光岳楼的3个模型进行对比分析。得出高台基对上部木结构的水平振动放大了3.8倍,在计算地震作用时不容忽视;考虑土与结构的相互作用,顶层水平振动相对于其他两个模型分别放大了2~3倍和9~10倍,因此,在计算地震作用时更能反映光岳楼的实际情况。

Guangyue Tower is located in the ancient city center of Liaocheng city in Shandong Province. As the national key cultural relic protection unit, Guangyue Tower was built in 1374. This paper establishes three models, which are timber structure, timber structure-tower base and timber structure-tower base-foundation. The first 8 natural frequencies and vibration modes of 3 models was gotten through modal analysis. Lanzhou wave was chosen to analyze the seismic response of Guangyue Tower, and the amplitudes were adjusted to 55 Gal and 310 Gal respectively according to the frequent earthquake and rare earthquake, which were inputted to the above models. As can be seen from the calculations, the horizontal vibration of timber structure was magnified 3.8 times by tower base, which could not be ignored in seismic response analysis; when considering soil-structure interaction, the top horizontal vibration of timber structure was magnified 2-3 times and 9-10 times with respect to the other two models, so considering soil-structure interaction in seismic response analysis could better reflect the actual situation of Guangyue Tower.