Study On Seismic Performance Of External F-D Buckling-Restrained Brace

As the requirements for seismic performance of building structures in China have increased,Buckling-Restrained Brace,as a reinforcement method for efficiently improving the seismic performance of building structures,has entered a new stage of research.The new direction of Buckling-Restrained Brace seismic performance research.At the same time,with the advancement and development of construction technology,the transformation of old and new kinetic energy forms is becoming more and more important for the reinforcement of existing buildings.Therefore,this paper uses the Mandelbrot fractal function as the theoretical basis to design an F-D BucklingRestrained Brace(Fractal-Dimension BRB)with fractal characteristics and disordered natural attenuation state.By studying the F-D Buckling-Restrained Brace under different parameters,it is located outside the building Reinforcement performance,analysis of its performance in seismic reinforcement,provides reference for research on seismic reinforcement and vibration control of existing buildings.To this end,this article conducts research from the following aspects:(1)In order to study the effect of the new F-D anti-buckling brace on the seismic performance of externally reinforced buildings under different parameters,this paper designs 25 different parameters of the anti-buckling brace all-steel core unit,which is analyzed by ABAQUS finite element simulation.The simulation analysis results show that: the width-to-thickness ratio has a significant effect on the seismic performance of the model,and the model with the larger width-to-thickness ratio exhibits superior seismic performance;the aspect ratio has less effect on the seismic performance of the model,and the lag Energy dissipation performance;the core yield strength has a certain effect on the seismic performance of the model,of which the high yield strength core is beneficial to improve the seismic performance of the model;the fractal dimension D has a greater impact on the seismic performance of the building,that is,the degree of core weakening It has a greater impact on seismic performance.Therefore,according to different working conditions,reasonable selection of different design parameters can better improve the seismic performance of the building.(2)In order to verify the correctness of the finite element simulation,an external F-D Buckling-Restrained Brace reinforcement structure under working conditions was selected.Based on the results of the ABAQUS finite element analysis,a set of external F-D Buckling-Restrained Brace frame reinforcement was designed.The scale test of quasi-static test.The test results are compared with the results of the finite element analysis.The research results show that the external F-D Buckling-Restrained Brace reinforcement exhibits good hysteresis performance.The weakened points designed based on the fractal function have obvious strain changes and hysteresis curves.,Skeleton curve,stiffness degradation and energy dissipation coefficient have the same trend as the finite element simulation results.(3)In order to further study and verify the seismic performance of the reinforced building with external F-D Buckling-Restrained Brace,combined with the results of pseudo-static research,a finite element model of a six-story steel frame structure was established,and three different strengths were selected.With the ground motion input,the variation rules of the building floor displacement,the floor displacement angle,the top floor acceleration and the base shear force under different ground motions are studied.The analysis results show that the externally installed F-D BucklingRestrained Brace reinforced building structure has good seismic performance,provides a certain lateral stiffness for the building structure,and can effectively limit the deformation of the building structure under ground motion,and is an earthquakeresistant reinforcement for existing buildings.The design provides a certain reference value.