Modeling structural behavior of reinforced concrete beam–slab substructures subject to side-column loss at large deflections

Abstract

This article proposes an energy-based method to determine the collapse resistance of beam–slab substructures subject to side-column removal scenarios. These include the removal of intermediate columns along the edge or those at corner. Four contributions to the internal energy dissipation are taken into account, including extension of reinforcing bars in the slab and beams, sectional bending moment at plastic hinges of beams, sectional bending moment along yield lines of the slab, and additional resultant bending moment from membrane forces in the slab and tensile forces in beams. The performance of the proposed method is validated against existing experimental results. A comparison of collapse mechanism of substructures subject to these two side-column removal scenarios is made in detail. It is found that no tensile catenary action developed in the beam for the removal of a corner column. The energy dissipation due to the extension of reinforcing bars and additional resultant bending moment contributes most to the resistance of substructures at large deflections. The proposed method can accurately capture the main collapse mechanisms of beam–slab substructures at large deflections, thus providing an accurate prediction of its progressive collapse resistance.