Research On Mechanical Properties Of Key Parts Of Special-shaped Steel Box Arch Bridge

The Xinqiao Bridge on the Ji-Qi high-speed connection line is a through-type steel box tied arch bridge.The key parts of the bridge are complicated in structure and stress.Based on the overall analysis of the arch rib,the most unfavorable and most representative key parts of various components are selected for local fine finite element analysis.The main work and results are as follows:(1)According to the results of the finite element analysis of the arch rib space,three representative key parts that need local analysis are identified:the lifting lugs of the side arch,the lifting lugs of the middle arch and the foot of the arch.(2)The calculation method of local analysis is studied and compared,the modeling method of the key parts,the interception principle,the selection of element types and the application method of boundary conditions are determined.(3)The local space finite element analysis is carried out on the lifting lugs of the side arch.The research results show that the equivalent stress and the maximum shear stress of the lifting lugs model of the side arch do not exceed the strength value of Q345 qD.The structural design of the connection between the lifting lugs and the arch rib can meet the strength requirements required for engineering safety.(4)The local space finite element analysis is carried out on the lifting lugs of the middle arch.The research results show that the equivalent stress and the maximum shear stress of the middle arch lifting lugs model with middle stiffeners do not exceed the strength value of Q345 qD.Yield failure has occurred in the local area of the middle arch lifting lugs without middle stiffeners.The stiffening plate in the middle of the middle arch lifting lugs can significantly reduce the stress concentration to achieve the purpose of increasing stability.(5)The local space finite element analysis is carried out on the arch foot.The research results show that the stress concentration of the arch abutment mainly occurs on the left,bottom and right side of the steel plate at the connection between the arch abutment and the arch rib.The maximum stress of the steel plate appears in the upper right corner of the steel plate at the junction of the arch abutment and the arch rib.The maximum stress of the arch rib appears on the left side of the arch rib near the bottom.