Numerical Investigation of the Progressive Collapse of the Reinforced Concrete Wall-Frame Structures Considering the Soil–Structure Interaction

In this essay, the progressive collapse resistance of the reinforced concrete wall-frame structures was evaluated with and without considering the soil–structure interaction. The vulnerability of the frames against progressive collapse was investigated with the middle column removal scenario from the first story, based on the sensitivity index. To evaluate the effects of soil–structure interaction, the wall-frame structures along with the soil (hard soil) and foundation were simultaneously modeled in FLAC software and compared with the frames in Seismostruct software. The results showed that the sensitivity index decreased by considering the soil–structure interaction in the wall-frame structures. Afterward, a parametric study of the structures (foundation thickness) and substructures (soil types, soil densities, soil saturation conditions and soil layers) was performed. The results showed that with an increase in thickness of the foundation, the sensitivity index increased, and therefore, the condition of the structure would be more critical against progressive collapse. It was found that high groundwater levels in the subsoil can reduce its bearing capacity and lead to the damage to the structure. In addition, it was determined that by changing the substructure soil type from type 4 (Clay-MC) to type 1 (Rock), the use of layer 1 (SM) and layer 2 (SM-CL/ML (Very hard clay)-SM), and the soils with high density, the condition of the structures is better to prevent progressive collapse.