Variational analysis in safety assessment for slab-shaped reinforced concrete structure's load plate in gas explosion
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摘要: 为快速评定民用建筑在燃气爆炸后的安全性,需要确定爆炸作用在结构上的荷载值。本文中通过变分法中的伽辽金法,从虚位移原理出发,推出燃气爆炸时的面荷载作用值与钢筋混凝土板的几何边界条件、最大挠度、抗弯刚度间的函数关系。结合建筑物爆炸后现场检测的板的最大挠度数据,反推该次燃气爆炸时混凝土板的伪静荷载值,该值在运用数字模拟燃气爆炸过程中管道侧壁面的上压强值范围内; 该数值与有限元精确解的误差约2%。再用该伪静荷载对结构进行静力分析,为快速评估结构安全提供参考。结合建筑物爆炸后的检测,对可能引起燃气爆炸的房间楼面提出了防止连续倒塌的构造措施。Abstract: It is necessary to determine the greatest possible load that a civil building can bear in a gas explosion in a quick safety assessment of the building. In this paper, according to the principle of virtual displacements, we derived the function relationships between the slab's surface load and its bending stiffness, maximum deflection, flexural stiffness and geometric boundary conditions, at the time of gas explosion, using the Galerkin variational method, and reversely we derived the slab's pseudo static load and maximum deflection by combining them with the slab's maximum deflection collected in the actual in-situ explosion test. The result shows that the pressure curve range of the sidewall falls within the numerical simulation results of the gas explosion, with an error of only 2% between the method and the finite element method. The static analysis of the structure in combination with the pseudo static load can provide a reference for the rapid assessment of structural safety. Also, following the site check of the building after the explosion, we proposed constructing measures for preventing continuous collapse that might result from gas explosion in a civil building.
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Key words:
- reverse bang size /
- safety assessment /
- Galerkin method /
- blast-resistant measures
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