Research On Rapid Construction Technology Of Small And Medium Span Steel Bridge

Against the background of the rapid development of steel production and bridge construction in China,this thesis analysed,studied and designed the standardization of medium and small span steel bridges.At the same time,it deeply analysed the influence of key problems of steel bridge joint connection on the structure quality.It provides a theoretical support for accelerating the construction cycle of bridges and ensuring the quality and safety of completed bridges and construction process.The thesis contents and results are as follows:1.Through the summary and analysis of bridge rapid construction technology at home and abroad,the rapid construction technology are integrated into the design and construction of steel girder bridges,and the economic analysis are made from the initial construction cost,maintenance cost and life-cycle cost of small and medium-span steel bridges,and the economic feasibility of the construction of small and medium-span steel bridges is given.2.According to the basic structure,design requirements and design calculation theory of steel girder bridges,the corresponding finite element models are established with the local specific size of the bridges as variables,and the standardized design dimensions of 20 m,30 m,40 m and 3×20 m,3×30 m and 3×40 m of simply supported steel girder bridges and steel truss girder bridges are analyzed and compared.Taking practical engineering as an example,the checking calculation process of small and medium-span steel bridges are carried out.The checking method to verify whether the overall strength and stiffness of the completed bridge meet the design requirements are given.This paper summarized and analysed the erection technology and quality pre-control technology of medium and small span steel bridges at home and abroad.Taking medium and small span steel plate girder bridges and steel truss girder bridges as the main research objects,considering the two construction methods of jacking and overall hoisting,according to the principle and characteristics of different construction methods,the construction process of steel girder bridges is simulated,and the static performance and quality pre-control of structures in each construction stage are systematically analyzed.The key points of control in the construction stage of medium and small span steel bridge are given.3.Aiming at the key problems of joint connection of steel bridge,such as the calculation of shrinkage strain of partial first-hole welding,stiffness and local strength of integral joint,and the influence of bolt reaming on the mechanical performance of steel structure bridge,the finite element models are established respectively for non-linear analysis.The results show that:(1)The maximum longitudinal shrinkage of members caused by fillet weld is not more than 0.504-0.540 mm,and the center of hole group at the joint is set up.The relative position accuracy of holes can be controlled by reserving 0.5mm shrinkage allowance.(2)The stiffness of integral joints has a great influence on the displacement,stiffness and stress of the structure.In design and calculation,joint articulation is recommended for the calculation of displacement,axial force and axial stress,while rigid joint is recommended for the calculation of bending stress,with a large safety factor.(3)About integral joints.Local strength,through calculating the stress analysis of arc edge,inner joint plate and butt joint with unequal width and thickness,the stress value of dangerous point of stress concentration is defined and concrete reinforcement measures are given.(4)The ratio of bearing capacity reduction coefficient y to area ratio x of steel plate enlargement and normal hole satisfies a linear relationship,and the linear regression equation is as follows(10)-(28).x.y1768118790.