无梁板用支撑柱加固后的冲切抗力分析

Punching-shear resistance of flat-slab strengthened by supporting poles

无梁板应用广泛。其在特殊情况下(如灾害、战争等)的加固具有重要意义。所述加固法为增设支撑柱,即在柱连线中点和柱网格中心处(五点)及仅在柱网格中心处(一点)增设支撑柱为最佳的两种情况。文献犤1犦用塑性分析的屈服线理论能量法进行加固后的弯曲抗力分析,本文则进一步充实了弯曲抗力分析的理论依据,并给出了可用于工程定量计算的公式。取一种最不利于在塑性状态下工作的无梁板配筋形式为实例,进行了加固后的理论计算比较犤2犦。结果表明:加固后的结构抗力较原结构提高1.3～4.0倍,根据已经发表的实例实验报告,其实际的抗力将远高于此值。因此,用支撑柱加固无梁板的方法理论上是合理的、安全可取的,而且实际操作简便易行,尤适合于应急加固工程。

There are two methods for strengthening flat-slabs: five-point supporting at the middle points of the lines linking two columns and the middle of column-net, and one-point supporting at the middle of column-nets. The bending capacities was analysed using the energy law of yield line theory. An example was given for evaluation and comparison. The results demonstrate that the load bearing capacity of the strengthened structure is 1.3-4.0 times as large as the original structure, and the actual capacity is much higher. The proposed method of strengthening flat-slabs is practical and reasonable.