Contribution of Floor Slabs on the Collapse Behavior of Reinforced Concrete Buildings

Abstract

Progressive collapse can lead to sudden cascading structural failures in a building which raise critical concerns due to its catastrophic consequences. Despite the recent rise of awareness about this topic, further investigation is needed to better understand the effect of initial failure on the subsequent progression of damage within the system and failure mechanisms. In this research, the behavior of structural components, including beams and slabs is investigated to demonstrate their ability to redistribute the loads after the sudden failure of columns or other elements and their effects. The goal is to help structural engineers better understand how reinforced concrete buildings behave during progressive collapse for the purpose of improving guidelines and approaches for designing new structures and evaluating existing structures concerning their potential for progressive collapse. In this research, a series of numerical analyses were carried out to assess the role of floor slabs (with and without beams) and their impact on the performance progressive collapse of reinforced concrete buildings. These numerical analyses were conducted with computer models that were validated using experimental data from an actual building and three laboratory specimens. SAP2000 (2023) and ELS (2023) software were used for linear and nonlinear dynamic analysis of three-dimensional models. Parametric computational analyses are carried out on one of the laboratory specimens and the test building to specifically examine the impact of slab thickness, number of spans, span length, number of stories in the building, presence of interior beams and perimeter beams, and flat slab systems. Based on the numerical analyses, it was concluded that the reinforced concrete slab thickness strongly influences the load redistribution when multiple columns are sequentially removed from the computer models. In addition, the calculated results indicate that the span length greatly affects the progressive collapse response, while the number of stories and number of spans in the building show slight effect on the structural performance.