Study On Mechanical Properties Of Precast Pier With Anchor Plate Semi-grouting Sleeve Connection

With the rapid development of precast assembly technology,it has been widely used in the field of bridge engineering.It has the advantages of short construction period,high efficiency,low pollution and high safety.Its application in the field of prefabricated bridge effectively solves the connection problem between pier column and cap beam,and the connection problem between components has been the priority among priorities of scholars at home and abroad.There are many ways to connect the traditional prefabricated structure,among which the grouting sleeve connection is the most widely used.Compared with the full grouting sleeve connection,the semi-grouting sleeve connection has the advantages of shortening the length of the sleeve,reducing the grouting workload,and ensuring the quality of construction and joint.This paper studies the precast pier with anchor plate semi-grouting sleeve and its connection through theoretical analysis and numerical simulation analysis,and carries out parametric analysis on the precast pier connected to analyze the influence of different parameters on the mechanical properties of the pier.It provides theoretical reference for practical engineering application.The specific research work of this paper is as follows:(1)By referring to the literature on grouting sleeve connection and precast pier research at home and abroad,and summarizing the research status and existing deficiencies in this field,the use of anchor plate in semi-grouting sleeve proposed in this paper is introduced in detail.(2)Based on the one-way drawing test of semi-grouting sleeve conducted by some scholars,midas FEA NX finite element software was used for numerical simulation,and concrete constitutive method was used to replace grouting material constitutive method.The simulation results were compared with experimental results to verify the applicability and accuracy of the modeling method.By comparing the numerical simulation results between the semi-grouting sleeve with anchor plate and the ordinary semi-grouting sleeve,the results show that the anchorage plate installed in the sleeve can meet the bearing capacity requirements of the semi-grouting sleeve,improve the stiffness of the sleeve to a certain extent,and reduce the tension deformation of the sleeve.(3)Based on the prefabricated pier test conducted by some scholars,the finite element model of prefabricated pier with semi-grouting sleeve connection is established by using ABAQUS finite element software.Based on the mechanical properties of the grouting sleeve,appropriate equivalent constitutive relation is selected to simulate the grouting sleeve in the form of "coarse reinforcement",and the simulation effect is good.By selecting an appropriate material constitutive model,the modeling method in this paper is elaborated,and the damage condition,hysteretic curve and skeleton curve of precast pier are obtained through calculation and analysis.The simulation results are in good agreement with the experimental data,which verifies the applicability and accuracy of the modeling method.The modeling method is used to preliminarily verify the influence of the welded anchor plate in the semi-grouting sleeve on the mechanical properties of precast pier.(4)Three sets of prefabricated pier models connected by ordinary semi-grouting sleeve and semi-grouting sleeve with anchor plate were established.ABAQUS finite element software was used for numerical simulation.According to the modeling method described above,the damage and failure state,horizontal bearing capacity,hysteresis curve,skeleton curve and residual deformation of the two sets of prefabricated pier were calculated,and the simulation results were analyzed theoretically.The results show that the larger the diameter of the longitudinal reinforcement,the larger the horizontal bearing capacity of the pier,the stronger the energy dissipation capacity of the model,the smaller the residual deformation,and the stronger the self-resetting capacity of the pier.In addition,it is found that the use of anchor plate can improve the bearing capacity and energy dissipation capacity of the pier to a certain extent,but it has little effect on the residual deformation of the pier.The feasibility of the application of anchor plate in practical engineering is analyzed,which provides a theoretical reference for the application of semi-grouting sleeve with anchor plate in practical engineering.(5)By comparing the effects of different sleeve lengths,different number of segments,different ferrule ratio and different coaxial pressure ratio on the mechanical properties of precast pier,the results show that: with the increase of sleeve length,the energy dissipation capacity of precast pier decreases,and with the increase of displacement load,the horizontal bearing capacity of the model decreases more obviously.As the number of precast segments increases,the energy dissipation capacity of precast pier becomes stronger,but the bearing capacity of precast pier decreases.With the increase of axial compression ratio,the upward spreading trend of pier model damage decreases and the horizontal bearing capacity of precast pier increases under the same load.