Bar fracture modeling in progressive collapse analysis of reinforced concrete structures

Reliable evaluation of progressive collapse resistance of structures requires substantiated methods and techniques for analyzing the response of critical elements subjected to large deformations. Steel bar fracture is a significant event that can lead to progressive collapse of reinforced concrete (RC) structures. Given the sudden discontinuity associated with bar fracture, modeling of such an event in a continuum domain analysis is challenging. In this paper a method is proposed for finite element modeling and analysis of RC elements that accounts for bar fracture. It is demonstrated that such a modeling technique is capable of developing catenary action. Analytical results based on the proposed method show good agreement with experimental data. The underlying cause for a drop in beam vertical resisting force following the peak force is identified and explained.