다중 각형 강재 유니트 내진보강시스템에 대한 연구

Abstract

In this study, A seismic strengthening system using multi steel tube unit was developed. This system applied the stiffness and strength enhancement method, which is an effective seismic reinforcement technique for the existing non-seismic buildings of middle and low-rise buildings. It was intended to compensate for the shortcomings of the existing seismic strengthening systems. It is designed to improve constructability through factory production and to allow for variability. In order to adopt an effective layout and bonding method with the existing structure, multi steel tube unit experiments were conducted. It was divided into two classifications according to the layout and two classifications according to the bonding method with the existing structure. As a result, the joining method using a square steel tube was more effective than the joining method using an steel plate at the point of lowering rigidity or maximum bearing capacity. In the joint method using steel plates, force transmission to the seismic reinforcement system was not performed well due to the destruction and separation of the welds at the corners. In order to verify whether effective seismic design and seismic strengthening are possible, a quasi-dynamic experiment was conducted on a specimen with non-seismic details of a two-story scale reinforced with a multi steel tube unit seismic strengthening system. After that, the results were compared through structural analysis. As a result, the specimen strengthened with the multi steel tube unit seismic strengthening system improved the stiffness and shear strength by 2.1-4.4 times and 2.1-2.8 times, respectively, compared to the specimen with non-seismic details. In addition, it was confirmed that the analysis results were more conservative than the experimental results. Therefore, it is judged that effective seismic design and seismic strengthening by applying the multi steel tube unit seismic strengthening system is possible. The purpose of this study was to prove the effective reinforcing effect of the seismic strengthening system for multi steel tube unit. Therefore, seismic performance evaluation was performed through a nonlinear static analysis of a frame model with a scale of five stories above the ground. As a result, the initial stiffness, strength, and ductility of the strengthened model were all increased, and the load resistance performance was improved.In addition, the effective reinforcement effect was demonstrated in accordance with the seismic performance standards.