Comparative nonlinear analysis of progressive collapse in steel and concrete moment frames

In recent years, structural failures due to the loss of gravity load-bearing members have increased, emphasizing the need to design both seismic performance and progressive collapse resistance. The type of structural system, building configuration, and retrofitting strategies play a crucial role in mitigating progressive collapse. This study aims to compare the performance of reinforced concrete and steel structures to assist in selecting appropriate structural systems for future critical projects. In this research, nonlinear static pushover analysis using the Finite Element Method (FEM), based on the Unified Facilities Criteria (UFC) guidelines, was employed to evaluate the progressive collapse potential of two medium-ductility moment-resisting frame systems (one reinforced concrete and one steel structure) designed in accordance with the Uniform Building Code (UBC). ABAQUS was used to analyze the structures. The study assessed the structures and the influence of structural types on reducing the likelihood of progressive collapse. The results indicate that corner columns in both RC and steel structures exhibit higher displacements compared to other columns. Furthermore, the maximum displacement in the concrete structure was approximately 25 percent higher than in the steel structure. Consequently, the concrete structure demonstrates a lower capacity to resist progressive collapse compared to the steel structure. In contrast, the steel structure exhibits greater resistance to progressive collapse.