Numerical Investigation on the Behavior of FRP-Retrofitted RC Exterior Beam-Column Joints under Cyclic Loads

This paper reports on the capability of nonlinear quasi-static finite element modeling in simulating the hysteretic behavior of FRP-retrofitted reinforced concrete (RC) exterior beam column joints under cyclic loads. For the purposes of our investigation, three concrete beam to column joint specimens (un-strengthened and FRP-strengthened) were selected. The ANSYS finite element software was used for modeling RC exterior joints. The specimens were loaded using a step by step increment procedure to simulate the cyclic loading regime employed in testing. Additionally, an automatically reforming stiffness matrix strategy was used to simulate the actual seismic performance of the RC members after cracking, steel yielding, and concrete crushing during the push and pull loading cycles. The results show that the hysteretic simulation is satisfactory for both un-strengthened and FRP-strengthened specimens. Furthermore, when FRP strengthening is employed, strengthened beam column joints exhibit a better structural performance than the un-strengthened specimens.