传统风格建筑塔式结构振动台试验及动力分析

Shaking table test and dynamic analysis on a tower structure in traditional style building

为研究传统风格建筑塔式结构在地震作用下的动力响应和抗震性能,以西安天人长安塔为研究对象,设计并制作了缩尺比为1/15的模型结构并对其开展模拟地震振动台试验。通过白噪声扫频获得该模型在不同水准地震作用后的自振频率、阻尼比等动力特性和刚度退化规律,并研究了不同水准地震作用下结构的动力放大系数、楼层位移及层间位移角、楼层剪力等动力响应。试验结果表明:在罕遇地震作用后模型结构损伤范围相对较小,楼板混凝土开裂主要集中在柱脚附近;结构自振频率和刚度随输入峰值加速度的增大逐渐降低,而阻尼比逐渐增大;结构顶部的动力放大系数明显高于其他楼层的;楼层剪力整体分布随高度的增加呈减小趋势,同一楼层上暗层的层间剪力较明层的大。采用OpenSees软件对模型结构建立有限元模型,并对天人长安塔原型结构进行了抗震性能评估。计算结果表明:8度多遇地震作用下结构的最大层间位移角为1/782,两个方向上基底剪重比分别为3.57%和3.78%;8度罕遇地震作用下,最大层间位移角为1/128,满足现行规范的限值要求。

To investigate the dynamic response and seismic performance of the tower structure in a traditional style building under earthquake motions,a specimen of Xi’an Tianren Chang’an Tower with a scale ratio of 1/15 was designed and fabricated and subjected to simulated seismic shaking table tests.The dynamic characteristics of the specimen,such as natural frequency,damping ratio,and stiffness degradation rule,were obtained through white noise frequency sweeping.The dynamic responses,including acceleration amplitude factor,floor displacement,inter-story drift ratio and shear force,were investigated under different earthquake intensities.The results indicate that the damage is relatively minor under rare earthquake excitation,mainly concentrates in concrete cracking near the column base.The natural frequency and stiffness slowly decrease with increasing peak acceleration,while the damping ratio increases.The acceleration amplitude factors at the top are notably higher than those of other stories.The overall distribution of shear force shows a decreasing trend with increasing height,with the dim stories being larger than the bright stories on the same story.The OpenSees software was used to establish the model and simulate the main results,and the seismic performance of the prototype structure was evaluated.It is shown that under the 8-degree frequent occurrence earthquake waves,the maximum inter-story drift is 1/782,and the base shear coefficients in both directions are 3.57%and 3.78%,respectively.Under the rare occurrence earthquake waves of 8-degree,the maximum inter-story drift is 1/128,which meets the requirements of the current design code.