Probabilistic progressive collapse analysis of steel-concrete composite floor systems

The paper presents a probabilistic analysis of steel-concrete composite floor against progressive collapse considering uncertainties in strength and ductility of steel connections. Using component-based connection model, an analytical framework for developing probabilistic connection models is proposed. The connection models developed are further introduced in probabilistic structure analysis against progressive collapse. Tornado diagram-based sensitivity analysis is performed to determine the influential random variables for structural resistance capacity. Using Latin Hypercube sampling of both random structure variables and external loads, random realizations of structures are generated and progressive collapse analysis is carried out using pseudo-static pushdown method. The proposed framework is applied to study the vulnerability of composite floor. Fragility curves corresponding to three limit states are developed. Discussions on the influences of steel connection and slab continuity on collapse vulnerability are given. Finally, results from the present probabilistic method are compared with those from deterministic approach.