| The building structure of our country is deeply affected by earthquake disasters because our country is located in the earthquake zones of the Pacific Ocean and Eurasia.However,because of the development of seismic design theory and the increase of fortification intensity,many existing buildings with non-seismic design or insufficient seismic design exist in seismic fortification zones in our country.Low hoop reinforced concrete frames are the main form of seismic design.As a widely used reinforcement technology,the steel sleeve reinforcement method has the advantages of simple construction technology,short construction period,remarkable reinforcement effect and good overall stability.The beam-column joint with insufficient hoop is the force transfer hub of the frame structure,the force is complex and the shear resistance is weak,and the brittle shear failure is easy to occur under the action of earthquake.Therefore,the quantitative research on the anti-seismic reinforcement technology of the beam-column joint with steel structure sleeve has significant engineering practical significance and large-scale industrial application prospect.The orthogonal beam has a key influence on the technical structure and effect of the beam-column joint reinforced by steel frame sleeve.On the basis of experimental verification,this paper,based on the simulation of 30 T-shaped beam-column joints and considering the influence of orthogonal beams,has carried out an in-depth analysis of the key parameters affecting the seismic reinforcement of the beam-column joints with steel sleeve,and explored the force mechanism of the seismic reinforcement of the T-shaped beam-column joints with steel sleeve,which provides a basis for the seismic design of the beam-column joints with steel sleeve.The main research contents are as follows:1.The finite element model of T-shaped beam-column joint low-cycle repeated loading test specimens was established,and the hysteretic curves and skeleton curves obtained by simulation were consistent with the experimental data,which verified the validity of the finite element method used in this paper;2.The seismic performance characteristics of beam-column joints strengthened with steel sleeve and unstrengthened beam-column joints in hysteretic curves,skeleton curves,specimen deformation,steel sleeve stress and crack development are compared,the failure mechanism and weak parts of specimens are defined,and the failure process of beam-column joints strengthened with steel sleeve under seismic load is analyzed;3.A systematic parameter study was carried out on the beam-column joints strengthened with steel sleeve,and the influence law of different parameters including the number of orthogonal beams,the width of reinforced plates in the core area,the distance between reinforced plates in the core area,the thickness of reinforced steel and the axial compression ratio on the seismic performance of the beam-column joints strengthened with steel sleeve was clarified,and the difference of the effect of different parameters was further compared and analyzed.The results show that with the increase of the number of orthogonal beams and the width of reinforced plates in the core area,the ultimate bearing capacity,energy dissipation performance and ductility of the specimens are obviously improved;The energy dissipation performance of specimens is improved significantly by decreasing the distance between reinforced plates in the core area;Increasing the thickness of reinforced steel improves the shear capacity of the joints;In a certain range,the increase of axial compression ratio obviously improves the seismic performance of the specimen but decreases the reinforcement rate of the steel sleeve. |
PDF Full Text Request