Experimental and Numerical Study of Outside Strengthening with Precast Bolt-Connected Steel Plate–Reinforced Concrete Frame-Brace

AbstractThis paper presents an outside strengthening method of existing frame structures with a precast bolt-connected steel plate–reinforced concrete (PBSPC) frame-brace. The working principle and advantages of the PBSPC frame-brace are introduced. To verify the retrofitting effectiveness of the upgrade system, quasi-static tests were conducted for three groups. The results showed that the peak load reached almost 3.6 times that of the nonstrengthening conditions, accompanied by larger initial stiffness and smaller lateral displacement. Numerical simulation models that showed ideal accuracy with the test results were presented based on Open System for Earthquake Engineering Simulation (OpenSees) software. Furthermore, parametric analysis was performed to demonstrate the optimization factors of the proposed upgrade technology, including, for example, brace height, steel plate size, and brace position. The proposed method plays a significant role in system-level upgrading and provides references for future studies due to assembly convenience.