混凝土框架结构抗震设计探讨

Discussion on the Seismic Design of RC Frame Structure

加强结构薄弱部位的抗震能力,是提高结构整体抗震性能的有效手段。本文通过对混凝土框架结构抗震特性及震害分析,认为框架结构的薄弱层在底层,建议框架底层设计为加强层,抗震等级提高一级。框架底层柱既是结构抗倒塌的关键构件,也是薄弱构件,加大其截面及提高混凝土强度等级,不仅提高了柱本身的抗震承载能力,还可以减少整体结构的侧移变形。框架最薄弱的部位在底层柱的上下端,在其部位增加抗剪斜筋,可以防止柱端过早出现斜裂缝。在底层室内地面处双向设基础系梁,锁定框架上部结构嵌固在基础系梁顶,这样可以控制底层的层高,减小底层柱高,是加强框架薄弱层及薄弱构件抗震能力的有效措施。

Strengthening the seismic capability of the weak parts is an effective measure to improve the whole structure's seismic performance. In this paper,according to the analysis of the antiseismic characteristics and earthquake damage of concrete frame structure,it is considered that the weak layer appears at the bottom,the suggestion of strengthening the bottom layer and improving the seismic grade are put forward. The columns at the ground floor is not only the key component,but also a weak component in structure collapse resistance of the frame structure. Increasing the section and enhancing the strength grade of concrete can improve the seismic capacity of the columns,also can reduce the lateral deformation of the whole structure. The weakest part appears at the upper and lower end of the columns at the bottom,increasing the shear-resisting incline bars in these parts could prevent early inclined cracks. Setting two-way foundation beams in underlying indoor ground could reduce the columns' height of bottom layer,which is an effective measure to strengthen framework weak layer and component and improve the seismic ability.