Numerical Analysis Of Seismic And Shear Behavior At Joints Of Segmental Assemble Bridge Piers

In recent years,with the rapid development of precast assembly technology in the field of civil engineering,the research and application of assembly bridge piers conforms to the trend of scientific development and it has received more and more attention.How to improve the shear capacity under the premise of ensuring the self-resetting ability of the segmental bridge piers has become one of new research directions of civil engineering.In the research,the seismic performance of reinforced concrete segmental piers and the shear performance of the joints are studied based on the previous research contents.(1)The processing method of ABAQUS finite element for reinforced concrete modeling is firstly described.The cast-in-place reinforced concrete pier and the unbonded prestressed segmental pier are established by ABAQUS to verify the effectiveness of the modeling method,the simulation of nonlinear contact and prestressed tendons increased.(2)Based on the model of the assembly piers of unbonded prestressed sections with energy-dissipating steel bars,the software of ABAQUS finite element is used to establish hollow-section assembly bridge piers,such as bonded prestressed tendons,semi-cast-semi-prefabricated,double shear keys and the energy-dissipating steel bars through the piers for quasi-static analysis.The results show that there is no significant difference in structural bearing capacity,energy dissipation capacity and self-resetting performance between the energy dissipating steel bars through the piers and the foundation model;the piers with double shear keys,bonded tendons and semi-castsemi-prefabricated can improve the structural bearing capacity in varying degrees,but the residual displacements of the piers with bonded tendons and semi-cast-in-place-semi-prefabricated segments are somewhat increased.The residual displacement of the pier model with double shear keys has no obviously change.(3)Based on the selected piers with double shear keys,the pier models with dry joints such as solid section,hollow circular section and hollow rectangular section are established.Seven kinds of shear key models are designed according to the amount,location and shape of shear keys under the same section type.And the shear behavior of pier shear bonds is studied with horizontal restraint stress and concrete strength as design parameters.It is found that the shear capacity of solid section is the largest,followed by that of hollow circular section under the same conditions;The shear capacity of rectangular shear keys is larger than that of prismatic and rectangular shear keys,and that of vertical double shear keys is larger than that of transverse shear keys under the same section;The models of four shear keys have the largest shear resistance capacity and are easy to stress concentration.The reduction rate of bearing capacity is also large.(4)Comparing the formulas of shear resistance capacity of AASHTO,Jiading Li and ATEP with the value of numerical analysis and testing,the results show that the value of AASHTO code formula in calculating the bearing capacity of joints are less than the value of testing and the numerical analysis,and it is suggested that suggested that the value of formula be enlarged by 1.16-1.19 times;The value of the bearing capacity formula proposed by Li Jiading is closer to the experimental and numerical results in calculating the bearing capacity of multi-shear keys;The error value of ATEP formula in calculating shear capacity between joints is large.The bearing capacity formulas of AASHTO,Jiading Li and ATEP do not consider the influence of shear key shapes and locations.