Study the seismic response of Reinforced Concrete Buildings Retrofitted with a Precast Concrete Frame Reinforced with a Steel Plate

Abstract

Most of the buildings that have been built prior to the adoption of the Syrian Arab Code in 1995 and its Annex (2) in 2005 are structurally inadequate to withstand seismic loads. Many of these buildings are still in use with varying levels of seismic deficiencies. This research highlights the importance of improving the seismic performance of frame buildings by using one of the retrofit methods to increase efficiency by increasing the resistance of existing buildings by using precast concrete frames reinforced with steel plate. The research investigates the seismic behavior of a 10-story mid-rise frame building using ABAQUS software. Firstly, the behavior of the precast concrete frame PBSPC, armed with inverted V-shaped, reinforced with steel plates, was obtained by creating an analytical model using the finite element software ABAQUS. A load protocol (displacement control) was applied. The efficiency of the retrofit was evaluated by applying several earthquakes to the building frame and comparing the seismic response by comparing the period, accelerations, floor displacements, and base shear forces before and after the retrofit. The results between the model and the laboratory experiment showed similar hysteresis loops. The results also indicated that the external retrofit mechanism using a precast concrete frame is highly efficient in improving the seismic behavior of the building in all placements. It was observed that the best results were obtained with the pyramidal method compared to other methods, where the lateral displacement at the top of the frame decreased by 58.8%, the acceleration at the top of the frame increased by 8.03%, and the base shear forces increased by 194.25%, while the period decreased by 67.91%. Regarding max story drifts, the pyramidal method provided the highest values of relative differences across all stories, ranging between 65.69% on the fifth story and 83.11% on the fourth story.