The doctoral thesis of the student Nour Al-Huda Sami Badr was discussed in the College of Engineering, University of Basra, Department of Civil Engineering, entitled A theoretical study to improve the area of connecting the column to the reinforced concrete beam under the influence of seismic loads
Within the research objective is investigated the seismic behaviors of non-seismic joints, intermediate design joints, and strengthening of non-seismic joints in frame building. For this purpose, six story frame building were designed according to objective of this research. The first frame assumed that the building was constructed by non-seismic joints with lack of transverse reinforcement in the joint panel, according to ACI 318-19 the reinforcement detailing requirements for intermediate moment frame used in the second building. Third frame great by strengthen non-seismic frame by CFRP materials using one layer covering the beam column joint with distance of 0.5m. The fourth model using two layers of CFRP to cover the beam column joint of the non-seismic frame building. The final model was made in the same way as the third model, but it used the CFRP's length at the 1.25-meter distance in the beam-column joint. The objective of reinforcing the frame structure in the beam-column joint area is to ensure the safe seismic performance as specified in ACI 374.2R-13.Finite element of frame buildings was performed to evaluate the seismic behaviors with full scale models. As previously indicated, following the experimental and numerical verification of the joint, the same element, material properties, and the procedure were followed in the model of joint is adopted to model the frame building by ABAQUS. El Centro earthquake loading was applied to the frame buildings. The frame buildings have same number of longitudinal reinforcements and dimensional size with the objective to compare the seismic behavior. The variables of research were the type of joints used in the frame buildings. Results reveal from numerical investigations on frame buildings based the performance that strengthening of beam column joint reduce the soft story failure mechanisms to occur which related to joint strength. The joint play pivotal role in the affect the seismic behavior of reinforced concrete frame buildings. The strengthening of non-seismic joint and seismic joints protects extent of the lateral displacement and decrease the roof displacement therefore reducing the lateral drift ratio demand, leading to meet the frame building to the life safety and immediate occupancy level of performance. In contrast, inadequacies of structural detail such as lack of transvers reinforcement in joints causes yielding of steel and cracks of concrete leading to collapse of frame building. The lateral displacement applied to the buildings to study the building behavior subject to lateral displacement. The result of lateral displacement versus load for all building models obtained by static analysis approximately captured the seismic performance of the building subjected to the El Centro earthquake.
