Simulation of reinforced concrete beam-column joints under cyclic loading

Reinforced Concrete buildings with 3 to 5 stories are common structures in Iraq. Recently and due to several earthquakes taking place at the borders and/or even inside Iraq, these structures are under the action of long-term cyclic loadings from these earthquakes. A major structural element in these RC structures is the beam-column connection which observes the energy from the earthquake shocks. Consequently, understanding the performance of these joints under reversed cyclic loading produced from repeating earthquake became necessary to understand the real capacity and behavior of these connections. One model is developed using the finite element software ABAQUS to represent a possible type of beam-column joint in any typical structure undergoing reversed-cyclic load from earthquakes. The suggested model offers a simple demonstration of the plastic mechanisms which determines joint behavior under shear loading created from repeating seismic actions. The model is subjected to reversed cyclic loading made from the peak value of actual earthquake applied at different timings after the joint reach yielding in the longitudinal reinforcement. The purpose of the study is to determine the energy and the remaining shear strength that the joint holds after it reaches the yield point after such reversed cycles. Shear capacity and deformations of the columns are calculated after each applied cycle gained from the earthquake and accumulated to know the total deformation after the cycles and to understand the response of that joint after each cycle and at the end. The results of this particular model indicate that it is suitable to be used in demonstrating the response of such type of joint undergoing cyclic loading.