大悬臂预应力混凝土盖梁空间受力分析

Spatial Stress Analysis of Great Cantilever Pre-Stressed Concrete Cover Beams

大悬臂预应力混凝土盖梁一般为跨高比较小的深受弯构件,内部体系受力复杂.为研究其空间受力特点,采用通用有限元结构分析程序建立三维块体有限元盖梁模型,对其进行施工阶段和使用阶段受力分析,并与相应梁单元模型进行对比.结果表明:实体模型及梁单元模型计算所得应力分布总体相同,但实体模型会出现部分应力集中现象;施工阶段分析应是此类盖梁结构设计的重点;盖梁悬臂段截面横向受力不符合平截面假定,局部出现应力集中现象.

Great cantilever pre-stressed concrete cover beams are usually deep with a low span-depth ratio and complex internal mechanical characteristic. To study the spatial stress characteristics, general finite element analysis software is used to build a three-D block finite cover beam, and the stress caused during construction phase and application phase is analyzed. This model is compared and contrasted with that of corresponding beam units. The results show that the stress distributions of the space beam model and the space solid model are roughly the same, although stress concentration phenomenon may occur to a part of the former; analysis of stress in construction phase is considered essential to designing cover beams of this kind; the cross-section transverse stress of the cover-beam cantilever does not accord with plane assumption in that partial stress concentration is produced.