Research On Anchoring Methods Of Bonded-Steel Reinforcement In Portal Frame

The bonded steel reinforcement technology can significantly improve the bearing capacity and stability of the portal frame structure.However,the anchoring of the joint part directly affects the working performance of the bonded steel plate.In this paper,two kinds of anchoring methods are proposed for the beam-column joints of ? and steel column joints.The mechanical properties of the anchoring method are studied by experiments,and the ABAQUS finite element model is established for comparative analysis.The main research work is divided into the following three parts:(1)Three beam-column joint test pieces of ? were designed and fabricated,including one comparative test piece and two test pieces after reinforced steel(the anchoring methods were GL-MG1 and GL-MG2 respectively).Through the static load test,the test phenomena,load-displacement curves,plastic hinge section strain,and strain section strain of each test piece were studied.The test results show that the stiffness,yield load and ultimate bearing capacity of the specimens strengthened by GL-MG1 and GL-MG2 anchoring methods are significantly improved,the strain of plastic hinges is significantly reduced,and the GL-MG2 method is more advantageous.(2)Three gantry rigid frame side column joint test pieces were designed and fabricated,including one comparative test piece and two test pieces after the bonded steel reinforcement(an anchoring method GZ-MG1,GZ-MG2).Through the static load test,the test phenomena,load-displacement curves,plastic hinge section strain,and strain section strain of each test piece were studied.The test results show that the stiffness,yield load and ultimate bearing capacity of the specimens strengthened by GL-MG1 and GL-MG2 anchoring methods are significantly improved,the strain of plastic hinges is significantly reduced,and the GZ-MG2 method has better performance.(3)Based on the actual conditions of the experiment,the ABAQUS finite element model was established for the GL and GZ specimens.The Cohesive internal cohesiondamage evolution model was used to simulate the finite element of the bonded layer.The results were compared with the experimental results.The correctness of the metamodel is studied,and the mechanical properties of the bonding layer are studied on the basis of the model.The research shows that the bond layer has positive stress and shear stress concentration in the end plate,plastic hinge area and steel plate cut-off,and the rubber layer peeling is easy to occur.In the parallel extension area,the shear stress and normal stress are relatively uniform.Through the above research,a comprehensive understanding was had in the mechanical properties of the bonded steel reinforcement technology in the field of light portal frame and the anchoring methods,which provide technical means and theoretical basis for practical engineering,and lay a foundation for further research in the future.