An experimental investigation of the progressive collapse resistance of beam-column RC sub-assemblages

The aim of the present paper is to evaluate the eventuality of progressive collapse of beam-column reinforced concrete (RC) structures employing a column removal scenario. An experimental program has been carried out to study the behavior of 5 types of laboratory-scale RC structures composed of one or three columns and two beams. The growth of damage within the concrete structure is analyzed using a Digital Image Correlation (DIC) technique. Two diameters of rebar (8 mm and 12 mm) and two beam lengths (180 and 240 mm) are considered to investigate the influence of the reinforcement ratio on the fracturing and bearing capacity of the one column-two beams structures. Sliding and pin connections are considered to evaluate the influence of the boundary conditions for structures consisting of three columns and two beams. The experimental results provide a failure scenario in four steps: elastic behavior, structural hardening with propagation of cracks through cross-sections of beams, yielding of rebars and growth of plastic hinges at beam-column joints, and the failure of longitudinal rebars. Finally, an analytical method based on the principle of virtual work is employed to calculate the structural resistance of the tested sub-assemblages and is compared to experimental data existing in published literature.