Study On Mechanical Behavior Of Steel Reinforced Concrete Joint And Anchorage Section Of Stiffening Girder Of Self-anchored Suspension Bridge

The self-anchored suspension bridge has a low requirement for foundation,beautiful shape and changeable shape of the bridge tower,such as the rectangular bridge tower of the Ping Sheng Bridge,the shell bridge tower of the bridge of hunting de bridge,and the lotus shaped bridge tower of this background engineering,forming a unique city landscape,which has a competitive advantage in the middle and small span urban bridges.Steel-mixed section steel box girder and concrete beam section,the two materials are different,the stiffness difference is huge,it is necessary to use complex structural measures to make the two together as a whole and synergistic force.The main cable is anchored to the stiffening beam by self-anchored suspension bridge.In order to transfer the main cable axis force to the stiffened beam,the influence of pulling force on the anchorage section of the main cable is reduced.The structure and stress of the anchorage section are both complex,and the stress distribution of the anchorage system is difficult to be accurately grasped.Based on the above reasons,detailed analysis is needed for the combined section and anchorage section.Based on the engineering background of Zhaohua Xiangjiang bridge,combined with the finite element analysis software,the following aspects are mainly analyzed:(1)The solid model of the steel mixing section is established by Midas FEA,and the stress situation of the combined section is analyzed under the bridge stage,the normal use limit state and the ultimate bearing capacity condition.Under different working conditions,the maximum longitudinal tensile stress of the steel member in the joint section is 82.4MPa,the maximum shear stress of the PBL shear bond is 20.7MPa,the maximum longitudinal tensile stress of the steel box girder is 164.5MPa,the overall stress value of the box girder is within the bearing range of the steel,and the steel structure is in a safe and reliable state.The maximum principal tensile stress of the joint section is 2.84 MPa,the maximum principal compressive stress is 21.4MPa,and the predominant anchorage position of the maximum principal compressive stress appears on the web.(2)The shear stress of concrete is close to the shear stress of different length shear bond,and the shear stress is close to the shear stress,that is,the shear stress of different length shear bonds is less affected by shear stress in the range of 1m range.From the pressure plate 1m to 2.5m,the length of the shear bond length on the bottom plate is similar to the maximum shear stress growth slope of the concrete.On the roof,the longer the shear bond length is,the smaller the maximum shear stress growth slope of concrete is,the smaller the shear stress value is,and the appropriate increase of the shear bond length can reduce the shear stress value of the roof.(3)The anchorage section solid model is established by Midas FEA,and the stress condition of anchorage section under the condition of completed bridge is analyzed.The maximum main tensile stress of the post anchorage plate is 99.4MPa,the maximum main tensile stress of the front anchorage plate is 45.8MPa,the post anchorage plate tube hole edge position,the main tensile stress value is between-34.2MPa and 15.9MPa.The main tensile stress in the anchorage zone is between-1.86MPa-2.34 MPa,the maximum principal compressive stress is 10.8MPa,and appears at the periphery of the pipe.(4)Comparison of the effects of three prestressed reinforcement on the anchorage force,there is no comparison of longitudinal prestressed reinforcement,anchoring web position longitudinal compressive stress is about 6MPa,the transverse prestressing anchorage section exists,the top surface of transverse stress 2MPa,vertical prestress,larger 3MPa stress vertical anchorage.