Variational analysis in safety assessment for slab-shaped reinforced concrete structure's load plate in gas explosion

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.