| With the further development of the economy,China’s existing two-dimensional transportation can no longer meet the needs of national construction,so there is a demand to build bridges to existing traffic roads.However,the previous construction process(cantilever construction,integral hoisting,step jacking,etc.)requires a lot of manpower and material resources,so the steel box girder traction construction technology with a series of advantages such as safe and reliable process,high degree of mechanization,saving manpower and material resources,not affecting the traffic under the bridge,and prefabricated production is widely promoted.However,with the emergence of more and more pulling bridges,researchers have found that the mechanical properties of steel box girder,guide beam and support pier should not be well grasped during the overall traction construction of steel box girder and guide beam,and it is necessary to carry out further analysis and research on the traction construction technology of steel box girder.Therefore,this paper relies on the high-speed cross-Qing yin Expressway construction bridge project,and studies the rapid construction scheme of steel box girder,theoretical analysis of bridge structure,finite element simulation calculation,construction monitoring and other aspects.The main work of this article is as follows:(1)Through reviewing relevant materials and on-site investigation,the overall assembly of steel box girder corresponding to this project,the single-point,one-way one-time pulling rapid construction technology corresponding to this project were studied,and the important construction process was deeply studied.(2)The finite element software MIDAS CIVIL was used to simulate the whole process of the overall traction construction of steel box girder,and the construction process was divided into 18 working conditions during the simulation,and the simulation analysis results of each working condition were summarized and studied,and the bending moment,stress,deformation and support reaction were analyzed,and 5 key construction conditions were further analyzed and studied.At the same time,the auxiliary components in the traction system of steel box girder are simulated to study the stress,deformation and buckling stability of the bracket.It also studies the stress,deformation and buckling characteristics of guide beams during traction construction.The results show that by studying the stress and deformation values of the steel box girder under five key construction conditions,it is further determined that the parameter values of the whole stretching process are within the allowable range of the specification,and the corresponding supports are in a uniaxial compression state.The stress value,deformation and buckling stability of assembled brackets and traction brackets also meet the construction technical requirements;The stiffness,strength and stability of the steel guide beam all meet the needs of auxiliary steel box girder traction.(3)According to the stress and deformation analysis and research of the local bridge section in the state of 13 working condition(the second maximum cantilever state of the steel box girder),the beam segment composed of 5 m on the left and right of the most unfavorable section of the working condition(Chapter 5 section 3)is used as the research object,and the simulation model of the local beam segment is established by using the finite mixed element method to analyze the stress and deformation changes of each component of the local beam segment under this working condition.The research results show that the stress level of each component of the local beam section of the steel box girder is within the allowable use range of the specification,and the deformation value of each plate is small,which can ensure the non-destructive construction of the internal components of the steel box girder during the pulling process(4)According to the finite element analysis results,the monitoring scheme of steel box girder traction construction was formulated,and the complete process stress and flexure deformation data was collected from the key section(see Figure 5.1),and the collected data was compared with the finite element simulation analysis results.Through comparative analysis,the on-site monitoring data is close to the theoretical simulation data,and then the rationality of the simulation is verified. |
