Damage and Failure of a Column-Supported RC Flat Slab Subjected to Impulsive Loading

Abstract

RC flat slabs supported by an array of columns subjected to the action of impulsive pressure were investigated. The slabs were designed for static loads according to current standards. The dynamic responses of 4 × 4- and 8 × 8-column-supported slabs were similar, as were damage and failure. A simplified model consisting of a tributary area and a central column yielded similar results, demonstrating the accuracy of the simplified model and its reliability. These analyses exhibited modes of damage and failure characterized by large shear distortions in the slab–column connection zone. The rest of the span remained undamaged and in a horizontal position. In all analyses, the slab concrete around the column was fully damaged. The rebars failed within a limited zone at the slab–column connections. The early failure of integrity reinforcement indicated that it could not fulfill its duty; thus, a subsequent progressive collapse scenario was inevitable. All bent-up rebars failed, and their contribution to shear resistance was doubtful. The static analysis was entirely different from the dynamic failure mode. Impulsive loading damage and failure were similar to those in the case of slab-on-slab impact; in both cases, the slab underwent large displacement and severe damage in the narrow slab–column zone, whereas the rest of the slab remained almost completely flat and undamaged.