某地下汽车库内两根柱子断裂破坏的原因分析

Analysis on the Reason of Two Columns Damaged in an Underground Carport

某地下汽车库内两根柱子断裂破坏 ,其余大量柱子及底板开裂。现场对车库内 85个沉降观测点的观测结果表明 ,车库周边基本没有上浮 ,中部上浮最大 ,呈现出有规律的上浮曲面 ,上浮变形引起的结构附加内力使车库部分柱子及底板开裂。将净上浮力作为均布面载 ,车库作为一个受此荷载作用的周边简支的空间空腹桁架进行整体计算 ,计算挠度与实测上浮的分布规律吻合 ,且部分柱子的内力计算值已远远超过其实际承载能力 。

Rupture failure of two columns,cracks in bottom slabs and many columns are found in an underground parking garage.The observed results of 85 subsidence points indicate that there is almost no displacement around the garage,the largest upward displacement is at the middle of the garage and a regular curved surface is formed.Huge additional internal forces caused by upward displacement make part of columns and bottom slab crack.In order to explain this phenomenon,this paper treats the net upward force as a distributed surface loads,and the garage as a space truss with simple supports that suffers such loads.Flexibility of calculation coincides with the measurement,and the calculation forces of some columns exceed far from their resistance capacity and reach to crack or failure statement.