Experimental and numerical investigation on progressive collapse resistance of RC frame structures considering transverse beam and slab effects

Abstract

In order to investigate the load carrying mechanisms in resisting progressive collapse for reinforced concrete (RC) structures while considering transverse beam and slab effects, a series of four 1/4-scale RC substructural specimens were tested and the failure modes, load-displacement relationships, and load redistribution responses are presented in this paper. Two beam-column subassemblies were tested as control specimens. The third specimen was a cross-beam subassembly composed of a transverse beam and a longitudinal beam which had the same reinforcement detailing as the control specimens to investigate the transverse beam effects excluding RC slab. The last specimen had identical beams with the third specimen, but including an RC slab to consider the slab effects, which could be used to simulate the mechanism to resist progressive collapse developed in a practical frame structure. Test results showed that the load-carrying capacity of a cross-beam system at the compressive arch stage was almost equal to the sum of the load-carrying capacities of these two crossed beams, whereas the transverse beam and slab effects could increase the capacity of a two-span beam by as much as 340%. Thus, transverse beam and slab effects should not be ignored in the simulation of progressive collapse for RC frame structures. Based on the simplified models calculating nonlinear static load-deflection responses for RC two-span beams proposed in the previous study and load-displacement relationships obtained in this test, computational models calculating load-deflection responses for cross-beam subassembly excluding or including slab were established and verified.