The effect of compressive membrane force and surrounding slabs on the behavior of flat slab structures in progressive collapse

This paper presents the dynamic analysis of flat slab buildings using macro modeling method to evaluate their progressive collapse resistance. In these analyzes, the post-punching behavior of slab-column connections is considered. The presence of lateral restraints, by development compressive membrane force in the slab, increases the stiffness and flexural strength of the slab and ultimately increases the punching shear strength. In continuous slabs, the lateral restraint is provided by the slab itself. In experimental testing, part of the flat slab structure is typically extracted in the tests due to cost reduction and limited test space, and an additional load is applied to the slab edges to simulate the influence of the surrounding slabs. The effect of compressive membrane action and surrounding slabs on the response of flat slab structures was investigated using a validated macro-model. The findings of the study indicate that the slab 's compressive membrane force enhances the ultimate load bearing capacity in the column removal scenario. This increase in bearing capacity of the structure is, of course, not proportional to the increase in punching resistance in slab-column connections. The results also indicate that ignoring the lateral restraint effect of the surrounding slabs underestimates the capacity of the substructure for load redistribution. It is suggested that rotational restraints be placed on the slab edges in order to simulate the effect of surrounding slabs on the behavior of the substructure.