| Steel bridge tower have been more and more widely used in bridge engineering across big rivers and bays due to their good mechanical performance,lightness and beauty.Steel-concrete connecting segment of tower column is an important structure to realize the reliable connection between steel structure and concrete structure of steel bridge pylons and then perform the function of force transmission.Most of the researches on steel-concrete connecting segment of bridge tower mainly focus on the force transfer mechanism and the analysis of local stress in the structure,but the structure of steel-concrete connecting segment is complex,and the guiding effect of the previous research results is limited.The main limitations are :(1)At present,domestic and foreign codes and existing literature have not specified the design of steelconcrete connecting segment of tower column,and there is a lack of corresponding design process;(2)The differences in mechanical properties and force transfer mechanism of different types of steel-concrete connecting segment structures have not been analyzed in detail;(3)There is still a lack of relevant research on the influence of structural dimension parameter variation on the force transfer and structural mechanical performance of steel-concrete connecting segment.In view of the above problems,this paper mainly carries out the following aspects of work through numerical simulation and obtains relevant conclusions:(1)The types and connection forms of the existing steel-concrete connecting segment of bridge towers are summarized,and the design ideas,design processes,related structural design methods and calculation processes of the bond section are given.(2)According to the existing codes and relevant literature,the steel-concrete connecting segment of the tower was designed,and the initial design parameters of each structure were given.The numerical simulation model of the steel-concrete connecting segment was established by using the finite element software ABAQUS according to the initial design parameters of each structure,and the mechanical behavior of each component was analyzed.The results show that the steel-concrete connecting segment of the tower column has reasonable force and reliable force transmission,and the steel-concrete connecting segment designed according to the above method is safe and reliable.(3)Through numerical simulation,the force transfer mechanism and mechanical performance of different types of steel-concrete connecting segment of bridge tower are compared and analyzed,the results show that the force transfer and mechanical behavior of back-plate-type and anteroposterior-plate-type steel-concrete connecting segment with cells are similar,however,the force transfer and mechanical behavior of front-plate-type steel-concrete connecting segment with cells are different from the former two.(4)The influence of different length and stiffness of steel tower transition section on the force transfer performance of steel-concrete connecting segment is analyzed,the results show that when the transition section of the steel tower has a certain length,the internal forces will be more uniform from the transition section of the steel tower to the steel-concrete connecting segment,so that the force and force transmission of each steel cell are more balanced;For backplate-type and anteroposterior-plate-type steel-concrete connecting segment with cells,when the overall stiffness of the tower transition section is increased by increasing the stiffness of the stiffener of the steel tower transition section,the force transfer ratio of the top surface of the inner filled concrete in the steel-concrete connecting segment will be increased.(5)In view of the large difference in force transfer and mechanical behavior between backplate-type(anteroposterior-plate-type)and front-plate-type steel-concrete connecting segment,the influence of different structural parameters(thickness of bearing plate,stiffness of shear nails,spacing of shear nails and length of steel-concrete connecting segment)on the force transfer and mechanical performance of the two types of steel-concrete connecting segment was analyzed,and a comparative analysis was made.(6)The influence of steel-concrete connecting segment slip on the force of the structure is deduced by the formula,the results show that the relative slip of the steel-concrete interface will increase the axial force and bending moment of the steel panel.The influence of the thickness of the bearing plate on the transmission ratio is explained theoretically,which also verifies the accuracy of the finite element model established in this paper. |
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