A computationally efficient numerical model for progressive collapse analysis of reinforced concrete structures

Abstract

Although marked advancements have been achieved to improve the computer power, progressive collapse analysis of large-scale reinforced concrete structures is still time-consuming or even impractical. In this study, a numerical model is proposed for efficient progressive collapse analysis of reinforced concrete structures. Recent advancements that can accurately and efficiently model the mechanical behavior of structural components are incorporated in the numerical model of reinforced concrete structure. The beams/columns, joint regions, and slabs are modeled by enhanced fiber beam element, macrojoint model, and layered shell element, respectively. In this way, the shear failure of beams/columns, failure of joints, and resistance contribution from floor slab can be taken into account for progressive collapse analysis of reinforced concrete structures. A six-story reinforced concrete frame structure is modeled using the approach proposed in this study. The progressive collapse of the structure is analyzed under column removal and direct blast loading scenarios. For comparison purpose, other popularly used finite element models are also adopted to carry out numerical simulations. The proposed model is proven to yield accurate simulation results with the least cost of time among all models. Based on the proposed model, parametric simulations are performed to investigate effective measures to improve the structural resistance to progressive collapse. It is found that increasing longitudinal reinforcement ratio in beams and columns can increase the catenary action capacity, but hardly increases the compressive arch action capacity. Moreover, the steel mesh reinforcement at top layer of slabs plays a significant role in resisting progressive collapse of reinforced concrete structures, which should be considered in design to resist progressive collapse.