Study On Seismic Behavior Of Reinforced Frame Joints With Different Axial-Pressure Ratio Strengthened By CFRP-Reinforced High-Performance Composite Mortar

HPFL(High-Performance Ferrocement Laminate)is a new method for strengthening the structure of cement-based inorganic high-performance composite materials in which both the reinforcing layer base phase and the interface agent are cement-based,and it is an ancient common steel wire mesh cement(The reinforcement results are greatly improved.However,with the deepening of the research and application of the reinforcement of the frame joints,the reinforcement meshes used as reinforcing phases,such as complicated construction layout,large welding workload,and difficult construction of reinforced steel mesh layers,are difficult to compound mortars.Disadvantages such as difficulty in compaction and compaction are also revealed.CFRP(Carbon Fiber Reinforced Plastics)has high strength and high efficiency in the reinforcement of concrete structures,and is easy to construct.It does not require large-scale construction tools and has good corrosion resistance and durability.In order to explore a stronger,more efficient,and more convenient method of reinforcement in construction,a carbon fiber mesh is used instead of the HPFL reinforcement method to provide reinforcement.Among the many factors affecting the seismic performance of the frame structure,the influence of axial compression ratio on the seismic performance of the frame joint is undoubtedly great.With the advancement of science and technology and the development of the times,high-rise buildings occupy a very important position in modern architecture.The axial-pressure ratio of the bottom-to-top frame beam-column joints has also been changing.The research on the seismic performance of CFRP mesh high-performance concrete composite mortar reinforcement joints with different axial-to-pressure ratios has important theoretical significance,but also has great Practical value,at the same time,the experimental conclusions can also provide important theoretical references for engineering practice,and provide more reinforcement methods for different axial-pressure ratio frame nodes that need reinforcement.In this paper,a total of four beam-column-joint specimens are set up,one of which is the comparative specimen ZYO,and the other three are the second force-strengthened test pieces ZY1,ZY2,and ZY3 at different axial compression ratios,among which the axes of ZYO and ZY2 The same pressure ratio,through the pseudo-static test analysis of the destruction of each specimen and failure mode,hysteresis curve and energy performance,skeleton curve,bearing capacity and ductility,strength and stiffness degradation,test specimen internal strain,etc.to compare the test The anti-seismic performance of the parts;and verified the test results by ANSYS finite element simulation and theoretical calculation analysis.The main conclusions are as follows:1.CFRP reinforced high-performance composite mortar is an effective way to reinforce the frame joints,and all seismic performance indicators have been improved and improved in different degrees.2.Within the range of axial compression ratio of this test,the strength of the reinforced specimen increases with the increase of axial compression ratio,the maximum bearing capacity increases in turn,and the maximum displacement and ductility decrease,and the strength degradation decreases.The stiffness degradation increases,which is due to(1)the increase of the vertical axial force can restrain the generation of cracks to a certain extent;(2)the increase of the vertical axial force can enhance the diagonal truss function of the core area of the node and improve the level.Direction of shear capacity;(3)The increase of vertical axial force can strengthen the restraint effect of the reinforcement layer on the core area;(4)The increase of vertical axial force can increase the adhesion between reinforcing steel and concrete in the specimen.The knot force and grip force reduce the shear deformation when the test piece is pulled out;the restraint effect of the reinforcement layer with the increase of vertical axial force decreases with the increase of the horizontal reciprocating load after the carbon fiber mesh is damaged.,But this can reduce the strength degradation of the test piece to a certain extent.On the whole,in the axial compression ratio range of the test,the seismic performance of the joint is improved with the increase of the axial pressure ratio.3.The reliability of the test results is verified by ANSYS numerical simulation and theoretical calculation analysis.The theoretical calculation formula provides theoretical guidance and reference for the practical application of the project.