高层建筑大开洞地下室顶板的应力分析

Stress Analysis of the High-rise Building Basement Top Slab with Large Openings

以上海某在建工程为背景,系统介绍了开洞较多的地下室顶板的嵌固能力。利用ETABS有限元软件建立了相关顶板模型,通过将地震作用简化为节点荷载作用在上部结构质心处,对楼板进行了应力分析,得到了楼板在多遇地震下和设防地震下的应力水平。分析结果表明,在多遇地震下的楼板应力基本小于1.0 MPa,可以满足小震楼板不开裂的要求;在设防地震和竖向恒载的共同作用下,楼板应力基本小于4.0 MPa,通过设计可以满足中震楼板钢筋不屈服的要求。地下室顶板具有较好的嵌固能力,可不考虑该楼板对上部结构产生的多塔效应。本工程鉴于安全性考虑,嵌固端设置在地下一层底板处。

Based on a project under construction in Shanghai, this paper presents the influence of the openings at the basement top slab on structural behaviors. A finite element model was established using the software ETABS. Seismic loads were simplified as nodal loads being applied on the centroids of the superstructures. Stress distribution at the top slab was obtained by stress analysis under frequent earthquakes and moderate earthquakes. The results show that （ 1 ） under the effect of frequent earthquakes, the stresses are less than 1.0 MPa and there is no cracking of the concrete in the slab; （2） under the combined effects of moderate earthquake loads and dead loads, the slab stresses are less than 4.0 MPa and there is no steel yielding in the slab. The effect of interaction between multi buildings does not need to be considered under the favorable fix end at the top slab of the basement. Considering the safety issue, the bottom slab of the I st floor basement structure was chosen to be the fixed end of the superstructure in this project.