Research On Structural Optimization Of Large-Span Curved Steel Box Girder Bridges

They are mostly used for urban bridges and complex terrain with obstacles or other structures.Although the curved steel wire girder bridge has many advantages,it is more complicated than the linear steel box girder bridge in terms of structural structure and mechanical properties,and it is not as sufficient as the linear steel box girder bridge in the amount and depth of research.Current research on curved steel box girder bridges has focused on the case of smaller spans,and less research on large-span curved steel box girder bridges.In this paper,several key parameters of long-span curved steel box girder bridges are designed and optimized for research.This paper first discusses the theoretical solution process of the distortion stress of curved steel box girder,and then takes the newly constructed large radius curved steel box girder bridge in a certain city as the research object,and uses ANSYS software to establish the curved steel box girder bridge plate element by finite element analysis Analyze the model,analyze the parameters and optimize the structure and structure of the long-span curved steel box girder,and provide design suggestions for the long-span curved steel box girder bridge.The research work in this paper is mainly carried out from three aspects:the radius of curvature,the position of the support,and the distance between the diaphragms of the long-span curved steel box girder bridge.The specific arrangements are as follows:1.Analysis of normal stress and distortion stress of steel box girder bridges with different curvature radii.Taking the newly constructed large-radius curved steel box girder bridge in a city as the research object,the theoretical solution process of the distortion stress of the steel box girder is discussed,and the ANSYS plate element model of the curved steel box girder bridge is used to study the steel box girder under its own weight and the lane load.Distortion stress is affected by the radius of curvature;2.Analysis of the influence of the setting position of the support on the normal stress and distortion stress of the curved steel box girder.With the help of finite element analysis software ANSYS,a full-bridge fine plate element analysis model is established,and its displacement and stress results under the action of dead weight and lane eccentric load are analyzed.In the calculation and analysis,the curvature radius of the curved steel box girder is 100m,160m,240m,and 400m,respectively;the position of the support adopts three position parameters of right,center,and left.12 parameter groups;3.Analysis of normal stress and distortion stress of curved steel box girder bridges with different diaphragm spacing.The key parameter of the structure:the distance between the diaphragms is used as the research parameter,and the influence of the distance between the diaphragms on the mechanical properties of the curved steel box girder is studied by finite element analysis.A total of 6 operating conditions are analyzed,among which the number of single-span transverse diaphragms of a box girder is 4,the number of single-span transverse diaphragms of two box girder is 6,and the number of single-span transverse diaphragms of three box girder is 9,The number of single-span transverse partitions of four box beams under working conditions is 12,the number of single-span transverse partitions of five box girder is 15 and the number of single-span transverse partitions of six box girder is 18,and the steel box girder bridges under all analysis conditions are The radius of curvature is taken as 100m.The research and analysis reached the following conclusions:1.When the radius of curvature is 400m and the bearing position is to the right,the control effect of the box beam section displacement,normal stress,shear stress,and distortional shear stress can be optimized at the same time.2.Under the action of dead weight and lane load eccentricity,the maximum value of each measuring point position of the box beam section appears in the mid-span section.With the increase of the number of diaphragms,the displacement increases first and then decreases.The value of the number of partitions is the smallest between 9-12.