Analysis Of Seismic Performance Of The New Self Centering Buckling Restrained Brace And Its Steel Frame

With the lateral restraint effect of the external restraint member on the energy dissipating core material,which made the core material of the buckling restrained brace having energy dissipation behavior in tension and compression,and improved its compression bearing capacity and energy dissipating capacity under the reciprocating load.Buckling restrained brace played the role of fuse,and effectively protected the main structure.However,buckling restrained brace mainly resisted the earthquake action through its strength and rigidity,so it had a large residual deformation after the earthquake,which maked the structure unable to continue to use and difficult to repair after the earthquake,resulting in a large economic loss,so controlling the residual deformation of the structure is also a key step in the seismic design.Therefore,it is of great significance to develop a self-centering buckling restrained brace which can not only dissipate seismic energy but also reduce residual deformation.In this paper,a new type of self-centering buckling restrained brace was proposed.The seismic behavior of the brace and its structure is studied by theoretical analysis and numerical simulation.The main contents of this paper are as follows:(1)This paper presented a new type of self-centering buckling restrained brace,introduced the concept and structure of the brace,design method,working principle and restoring force model,and gave the optimal configuration between the restoring bar and the energy consuming core material,and on this basis,gave the performance evaluation index of the self-centering buckling restrained brace.(2)Based on the finite element software of ABAQUS,the model of the self-centering buckling restrained brace the was established,and the reliability of the modeling method is verified by experiments.Then,the stress mechanism is analyzed.On this basis,the influencing factors of the seismic performance of self-centering buckling restrained brace were analyzed.The results show that the larger the area of the restoring bar is,the larger the second stiffness of the brace is,the larger the area of the restoring bar is,The self centering capacity is increased by 46%,but the energy consumption capacity is reduced by 37%;it is suggested to use low initial prestress;it is suggested that the reduction degree of cross-sectional area of core material pipe should not exceed 50%;the size of slenderness ratio should be determined according to the actual engineering needs,but should not exceed 66.(3)The finite element models of self-centering buckling restrained braced steel frame and buckling restrained braced steel frame under two principles were established and time history analysis was carried out.The results of time history analysis show that self-centering buckling restrained brace is better than buckling restrained brace in controlling the seismic response and reducing the residual deformation of the structure;scbrb-mf1 designed based on the equal strength principle had relatively good energy consumption capacity,and the axial force of the brace was relatively small,which effectively reduced the adverse effect on adjacent members and the setting of the brace nodes The scbrb-mf2 based on the principle of equal core material pipe area was relatively good in the control of displacement response,interlayer displacement angle and residual deformation,which could reduce the cost and difficulty of post earthquake structural repair.