Experimental And Theoretical Study On Seismic Behavior Of Steel Frame Structures With Buckling Restrained Braced

Buckling restrained brace is an effective energy dissipation component,which can effectively improve the stiffness and energy dissipation capacity of the frame structure.At present,there are perfect research systems on buckling restrained braces at home and abroad,but there are relatively few studies on steel frame structures with buckling restrained braced,and there is a lack of systematic research.In this paper,a low-cycle reciprocating test study was carried out on three specimens of the steel frame structure with buckling restrained brace,and the experimental results were analyzed in depth.The finite element analysis model was established by ABAQUS software.The frame structure,which the beam-column joints using semi-rigid connections,was selected to establish a full-scale standard model for parameter analysis.The main research work was as follows:(1)In this paper,a pseudo-static test had been carried out on three specimens of buckling restrained braced steel frames.The seismic performance and failure mode of buckling restrained steel frames were studied with the parameters of rigid connection,hinged connection and semi-rigid connection.According to the test results,the hysteretic curves and skeleton curves of horizontal load(P)-horizontal displacement(?)of each specimen were compared and analyzed,and the influence of different connection methods of beam-column joints on the mechanical properties of the frame structure was studied.(2)Based on the skeleton curves extracted from the test data,this paper made an in-depth analysis of the test results.Firstly,the influence of different connection methods of beam-column joints on the initial stiffness and bearing capacity of the structure was observed by the eigenvalues of skeleton curve.Moreover,the ductility,strength degradation,stiffness degradation and energy dissipation capacity of the steel frame with the buckling restrained braced were evaluated by calculating each coefficient.In addition,comprehensive evaluation through detailed analysis of the rotation deformation of the buckling restrained braced at each key position and the strain change of each key part of the frame.It can be seen that this type of frame structure has the advantages of good ductility and energy dissipation capacity,and provides the basis for the establishment of its theoretical analysis.(3)Based on the experimental research results,this paper considers factors such as material constitutive,contact processing,boundary conditions,loading methods,solving nonlinear equations,element selection and meshing,etc.,the mechanical models of three frame structures with buckling restrained braced were built respectively by ABAQUS finite element software,and the results of test and numerical calculation were compared and analyzed to verify the rationality and accuracy of the calculation model.(4)In this paper,on the basis of the above model,considering the practical engineering application,the finite element calculation model of the steel frame structure with buckling restrained braced was established as the standard model.Seven possible influencing factors were selected,and the specific parameters were set for comparative analysis.By summarizing the results of parameter analysis,the main influencing factors and influencing rules for the initial stiffness,yield capacity and ultimate capacity of this kind of structure were obtained,which provided a theoretical basis for practical application.