The effect of the composite floor on the robustness of a steel self-centering MRF under column loss

This paper presents the numerical assess of the robustness of a seismic-resistant steel building with self-centering moment resisting frames against progressive collapse. The numerical analyses were carried out using a 3D model developed in ABAQUS. The 3D model considers the effect of the composite slab, where composite beams and their shear connectors were modeled with a combination of shell, beam and nonlinear connector elements. All the beam-column and beam-to-beam connections were modeled using nonlinear connector elements with appropriate failure criteria, calibrated against previous experimental results. The self-centering moment resisting frame where a sudden column loss was simulated was modelled using 3D solid elements to accurately capture its local and global nonlinear behavior. Quasi-static nonlinear analyses were carried out to identify all possible failure modes and to investigate the effect of the floor slab on the overall progressive collapse resistance. Nonlinear dynamic analyses were also carried out to predict the true dynamic response and evaluate the acceptance criteria of current building design guidelines.