Research On The Influence Of BRB Support End Connection Structure On Force Transmission Mechanism

Buckling restrained brace,also known as anti-buckling brace,or BRB(Buckling restrained brace),is a new type of brace that integrates energy dissipation in tension and provides an organic unity of stiffness under compression.It has been widely used in the field of seismic resistance of building structures.The existing anti-buckling brace members and embedded parts mostly use welding connection,and the related research results are relatively rich,but the research on the friction high-strength bolt connection that is convenient for engineering installation is lacking.For this reason,the research on the use of friction high-strength bolts to connect anti-buckling brace members and embedded parts has great engineering application value.Based on the actual engineering of anti-buckling load-bearing brace using friction high-strength bolt connection,in order to verify the reliability of friction high-strength bolt connection,three different types of actual buckling restraint brace members were selected and subjected to axial compression load tests.According to the test phenomena and data sorting of the specimens,the load-bearing capacity and deformation performance of different types of specimens are analyzed.At the same time,the finite element analysis software ABAQUS was used to simulate the test specimens,and the rationality of the finite element simulation was verified through experimental comparison,and the bolt arrangement method of the brace connection section,the thickness of the auxiliary connection angle steel,the length of the brace connection section,and the connection method were further verified.Carrying out finite element parameter simulation analysis for four design parameters,focusing on the influence of friction high-strength bolt connection structure on brace bearing capacity and deformation mode.The research results show that the buckling restraint brace specimens of different cross-section sizes can show good bearing capacity performance in the axial compression load test.The buckling restraint brace specimens of 30 mm and 40 mm can be in the elastic compression stage,and the 20 mm thick buckling brace specimens can be in the elastic compression stage.The connection section of the buckling-constrained brace specimen has buckling instability due to stress concentration;the maximum bearing capacity of the specimen obtained by the simulation analysis is basically consistent with the yield bearing capacity of the member,and the error of the simulation and test results is within 10%;the pass is limited The force transfer mechanism of the buckling-constrained brace specimen is obtained by the meta-simulation.The force law of the test and the simulated specimen is basically the same.The three buckling-constrained brace specimens yielded before the inner core of the support due to the stress concentration in the brace connection section.The brace has buckling instability,the brace connection section is bent and deformed,and the brace as a whole is inclined to the left;through the simulation analysis of the design parameters of the brace connection,it is found that different parameters have different slenderness ratios on the three buckling restraint brace specimens And the influence of force transmission mechanism is different,which is mainly reflected in the different bearing capacity performance,anti-instability ability,stress change and deformation mode;through the comparison of different parameter simulation analysis,it can be obtained that the length of the buckling restraint brace connection section is appropriately shortened,and the connection section angle steel is increased.The thickness can effectively improve the bearing capacity of the buckling-constrained brace of the friction high-strength bolt connection;increasing the number of single-row bolts and increasing the length of the angle steel can reduce the stress concentration area of the supporting connection;the same buckling-constrained brace is welded The bearing capacity of the buckling-constrained brace of the connection mode is significantly higher than that of the buckling-constrained brace using the friction high-strength bolt connection,but the anti-instability ability of the brace is reduced.