隔震建筑概念设计的基本问题

Basic Problems in Conceptual Design of Seismic Isolation Building

在隔震建筑的设计过程中应首先进行概念设计,在总体上把握隔震结构设计的主要方面。本文论述了隔震建筑概念设计的基本问题。在概念设计阶段,首先应在目标设计概念指导下,综合隔震建筑安全性与投资水平的平衡,确定建筑是采用隔震结构还是抗震结构。在进行隔震设计时,应根据输入地震动的加速度幅值和主频,建筑的允许加速度等值确定隔震结构的固有频率;应根据隔震系数和隔震层的允许位移合理确定隔震层总体刚度的范围。对隔震建筑的上部结构,应选择有利房型,合理布置结构,减小结构的不利地震反应。

The conceptual design is to control the general direction in the process of designing seismic isolation structure. For a particular building, its structure can be seismic isolation or aseismic structure. The decision depend on a balance between seismic safety and investment. In general, a building with isolation structure is safer than that with aseismic structure. Isolation structure may be the only possible structure to meet high safety demand in the region with high basic seismic intensity. Isolation structure is also cheap in the region of seismic intensity above VII. The range of total stiffness of isolation layer is determined by isolative parametrs and admissible displacement of isolation layer. The isolative parameters include input earthquake acceleration and its basic frequency, admissible acceleration and damping of the structure. If the stiffness is larger than its upper limit, the acceleration of the structure will be too large. If the stiffness is lower than its lower limit, the displacement of the structure will be too large. The structure above the isolation layer should be with regular shape and arranged symmetrically to reduce eccentric seismic response. The structure also needs enough strength to keep safety of the building. The shear stress in isolated building should be above 70% of that in aseismic structure.