Numerical simulation of catenary action of hybrid FRP RC beam-column subassemblage under progressive collapse

In this paper, due to the role of the catenary action of the structural members in large deformations and transfer of additional loads due to the middle column removal is important to prevent the catastrophic event of progressive collapse, a simulation method is introduced using 3D numerical finite element method (FEM). This method is simple, reliable and very suitable for predicting the response of RC members to the failure level. For verification of numerical model, two series of specimens tested experimentally by previous researchers have been used. The first series include the beam-column subassemblages under a middle column removal senario for comparing and displaying the numerical modeling capabilities in the prediction of three levels of performance including flexural, compressive arc and catenary action and the second series include a set of concrete beams rienforced with hybrid combinations of steel and fiber Reinforced polymer (FRP) bars. Comparisons between the load-displacement curves obtained from experimental data and numerical results of both series of specimens reveal the high accuracy of the proposed simulation method. In the following of research, based on validated numerical models, the effect of FRP bars in combination with steel reinforcement on the performance of beam-column subassemblages under progressive collapse and the effect of mechanical properties and their arrangement in concrete beams section on the strength and ductility and catenary action are investigated.