Study On The Design Method And Mechanical Behavior Of Cable-pylon Composite Anchor Structure With Steel Anchor Beam And Steel Corbel

On the basis of summarizing and analyzing achievements of steel-concrete composite anchorage structure with steel anchor beam and shear connectors, the mechanical behavior of cable-pylon composite anchor structure with steel anchor beam and steel corbel and mixed shear connectors were studied through theoretical analysis and model test. And the design method of the steel-concrete composite anchorage structure was submitted. The main results of this dissertation are following:Elastic-plastic finite element numerical analysis was adopted in order to research load-transfer mechanism of the cable-pylon composite anchor structure. The numerical simulation with a finite element model took the nonlinear contact between steel slab and concrete into consideration, and bolt connection and initial relative position of steel anchor beam and steel corbel were simulated. Through this research, the load-transfer and distribution of stayed-cable force in steel anchor beam and steel corbel and the forced state of mixed shear connector composed with studs and perfonbond rib shear connectors under symmetrical and unilateral cable force were found out.The full scale test of cable-pylon composite anchor structure with steel anchor beam and steel corbel was carried out. Adopting the loading method, material, construct, and construction process of the full scale model which were the same as the real bridge’s. The stress distribution and change law of steel anchor beam and corbel and shear connectors, and stress and crack distribution of concrete under the cable force of finished bridge state, partial loading state, operation state and overload state were experimentally measured. The test results indicate that the anchorage structure is safe and reliable. By comparing the results of the test and the numerical analysis, it demonstrates that the result obtained from the numerical simulation method is accurate.The load-bearing capacity of cable-pylon composite anchor structure with steel anchor beam and steel corbel were studied through the approaches of elastic-plastic finite element analysis. Through this research failure mode of this structure, the deformation and stress of components of the anchorage system, the pattern of crack propagation in concrete, and the distribution of stayed-cable force in mixed shear connectors under loading complete process were get.Mechanical behavior of studs shear connectors and perfonbond rib shear connector in cable-pylon composite anchor structure with steel anchor beam and steel corbel were studied through the approaches of elastic-plastic finite element analysis. Based on the finite element model taken material nolinear and contact into consideration, the load-transfer mechanism and risk factors of mixed shear connectors under cable force were studied. Based on simulated the real boundary of shear connectors in the anchor structure, the shear capacity, shear stiffness, deformation and stress distribution of stud and perfonbond rib shear connector under loading conditions which are the vertical pressure of concrete pylon and horizontal force respectively were studied. And an expression for computing the shear capacity of a stud connector and perfonbond rib shear connector in cable-pylon composite anchor structure with steel anchor beam and steel corbel was proposed.The rational restraint manners for the steel anchor beam and connections types of steel corbel were selected. Based on the balance of space force, in different steel anchor beam′s restraint manners, the distribution of the horizontal cable force between steel anchor beam and concrete tower in the whole construction process was got. Through the finite element numerical analysis, the 3D space concrete tower finite element model was built, and concrete stress under different steel anchor beam′s restraint ways, concrete stress and shear force of shear connectors under different connections types of steel corbel were compared and analysised.Based on the above results, the force model and inner force formulas of key section of steel anchor beam and steel corbel and concrete tower were proposed, the design method of steel-concrete composite anchorage structure with steel anchor beam and steel corbel were put forward.