基础和屋顶隔震混凝土结构的地震振动台实验研究

Experimental seismic study of concrete structures with base and roof isolation systems

通过使用平面尺寸为4.0m×4.0m的地震模拟器即振动台,对基础和屋顶隔震体系的控制性能进行了比较研究。试验包括三个三层无隔震、基础隔震和屋顶隔震混凝土框架结构模型。屋顶隔震包括板和叠层橡胶支座(LRB)。输入振动台的模拟地震动分别是1940N-S地震动、人工模拟山东地震动和人工模拟上海地震动。通过分析三个三层模型在白噪音扫描下的动力特性,首先评价了基础隔震与屋顶隔震体系的控制性能。实验结果显示,尽管基础隔震与屋顶隔震有着不同的工作原理,但基础隔震和屋顶隔震体系都能够明显地减小结构的位移和加速度响应(包括层间位移)。而且前者有更好的有效性。值得注意的是,屋顶隔震体系由于实施相对方便,因而可能成为减小中低层建筑结构地震损伤的优先选择。

A comparative study has been carried out on the control performances of the base isolation and the proposed roof isolation with resort to a seismic simulator (i.e. shaking table) with the size 4.0m×4.0m in plane. The whole experiment in this study includes three three-story concrete frame structure models with no isolation, base isolation, and roof isolation, respectively. The roof isolation consists of the slab and the laminated rubber bearings (LRB) that support it. Three types of seismic ground motions, namely the El Centro 1940 N-S ground motions, the simulated Shandong artificial ground motions (SDW), and the simulated Shanghai artificial ground motions (SHW) are applied to the shaking table. The control performances of the base isolation and the roof isolation are first evaluated by assessing the dynamic characteristics of three three-story models under the white noise ground motion excitations. The experimental results show that, the base isolation and the roof isolation are all capable of reducing the displacement and acceleration responses (including the interstory drifts) of structures significantly, but the former can render better effectiveness with respect to the latter. Nevertheless, the proposed roof isolation has the potential to become an attractive way to mitigate the earthquake damage to low- and medium-rise buildings due to its easier manufacturing in comparison to the base isolation.