| Reinforced concrete structure is currently the most common structural form.However,the corrosion of steel bars will not only cause serious problems such as the reduction of the bearing capacity of the reinforced concrete structure and the destruction of the structure,but also increase the cost of maintenance and reinforcement.The fiber reinforced composite(FRP)reinforcement has excellent material properties such as light weight,high strength,and corrosion resistance.,Has gradually become one of the new choices of reinforcement bars for concrete structures in the engineering field.However,FRP is an anisotropic material.Compared with ordinary steel bars,FRP bars have higher tensile strength,but their shear properties are poor.The tensile strength of FRP tendons will be affected by shear failure under the action of earthquake reciprocating load.Therefore,the research on the seismic performance of FRP reinforced concrete beam-column joints has important engineering practical value.The current domestic research on FRP reinforced concrete structures focuses on concrete beams and columns,and there is still a lack of research on the seismic performance of frame beam-column external joints.As the most complex and most important component in the structure,the external joints of the frame are likely to cause the overall structure to collapse when damaged.Therefore,the research on the seismic performance of the external joints of the FRP reinforcement beam-column is the key link in the development of the FRP reinforcement concrete seismic frame structure.On the basis of test calibration,based on the simulation analysis results of 30 T-shaped external joint specimens,the key parameters affecting the seismic performance of FRP reinforced concrete beam-column external joints are analyzed.The research results clarified the force mechanism of FRP reinforced concrete T-shaped external joints,and improved the seismic design method of FRP reinforced concrete beam-column external joints.The design method provides the basis.The specific research contents and conclusions are as follows:1.The existing T-shaped external joint test data results are compared with the finite element simulation results,and the consistency between the two in terms of hysteresis curve,skeleton curve,stiffness degradation curve and failure form is confirmed,which verifies the simulation used in this paper.Effectiveness of the method.2.Detailed analysis of the hysteresis curve,crack development process,concrete compressive stress comparison and FRP tendon tensile stress value and shear stress value results of FRP bar concrete joints from loading to failure process,clarified the failure mechanism of the members,and analyzed the joints The mechanical behavior of FRP bars under low-cycle reciprocating loads.3.The parameters that may affect the seismic performance of FRP reinforced beam-column external joints include beam end shear span ratio,beam stirrup reinforcement ratio,beam longitudinal reinforcement ratio,core zone stirrup spacing,and core zone stirrup reinforcement The effect of the parameters such as the rate and the fiber types of FRP tendons is compared and analyzed.The results show that the beam-end shear-span ratio,the stirrup spacing in the core area,the reinforcement ratio of the beam longitudinal reinforcement and the fiber type of the FRP reinforcement have significant effects on the seismic performance of the member. |
