现有结构抗震设计方法一般采用基础嵌固假定,忽略基础刚度对上部结构抗震设计的影响。实际上,客观存在的基础刚度将改变建筑结构的地震作用及效应。提出基于有限基础刚度的结构计算简图,研究基础刚度对高层建筑地震作用及效应的影响规律,可以较好解释汶川地震中底层框架柱上端破坏的原因,有利于进一步完善高层建筑抗震设计。分析基础刚度对高层建筑侧移刚度以及整体稳定的影响,提出高层建筑合适基础刚度的理念、计算方法及隔震结构基础竖向刚度要求。
Most of the state-of-art structural earthquake-resistant design methods are based on embedded-fixed-end assumption and the effect of foundation stiffness on superstructure is not considered. Foundation stiffness, however, will change structural response and behaviors under earthquake action. In this paper, structural calculation diagrams based on finite foundation stiffness are proposed. The effect of foundation stiffness on earthquake responses of high-rise buildings is studied, and this trial gives reasonable explanations for common structural failure at the upper end of bottom frame columns in Wenehuan earthquake disasters. The influence of foundation stiffness on structural lateral stiffness and overall stability is investigated, and the concept and calculation methods of appropriate foundation stiffness for high-rise buildings are put forward. In addition, the minimum value of vertical foundation stiffness for seismic isolation structures is also calculated.