Spatial Effect Analysis Of Small Radius Steel Box-Concrete Curved Girder Bridge

With the rapid construction and development of highways and municipal transportation infrastructure,the society’s requirements for transportation facilities are increasing.Highway bridges and municipal bridges are undergoing transformation and upgrading.Steel box-concrete composite structures are gradually used as new structures in urban interchanges and High-speed interchange ramp bridge.Due to site constraints,most interchanges and interchange ramp bridges are curved bridges with a small radius.The small radius steel box-concrete composite curved girder bridge,as a kind of spatial structure,has a significant spatial effect under the dual influence of "bending-torsion coupling" and "steel-concrete combination",so it has attracted long-term attention from academia and engineering.Taking a high-speed interchange ramp bridge as the engineering background,this paper carried out the space simulation method,the eccentric load effect and the anti-overturning performance of the small radius steel box-concrete curved girder bridge.The main research contents and results are as follows:1)Summarize the stress characteristics and different analysis methods of curved bridges,and discuss the simulation accuracy of the beam lattice model and the plate-shellsolid model on the steel box-concrete composite beams based on the use of the threedimensional finite element simulation method of the supporting project.The normal stress,deflection and bearing reaction results calculated by the model are compared to verify the correctness of the established model,clarify the applicable scope of the two modeling methods and reveal the force mechanism of this type of bridge structure.2)In view of the difference in force and deformation of the inner and outer box girder of the steel box-concrete composite curve bridge,Midas/FEA is used to establish a space simulation model based on the slab-shell-solid method,and through the normal load and eccentric load of single and double lane loads,Analyze the deck stress of the combined curved girder bridge and the stress and deflection of each control section of the inner and outer box girder as well as their corresponding eccentric load coefficients,give suggestions for the value of the eccentric load coefficient of the main girder along the longitudinal bridge direction,and discuss the radius of curvature and high span The influence of basic parameters such as ratio,web thickness,and bottom plate thickness on the stress,deflection and eccentric load coefficient of the mid-span section of the main girder provides a reference for the design of similar bridges.3)In view of the uneven reaction force of the inner and outer bearings of the steel box-concrete composite curve bridge in the process of spatial stress,Midas/civil is used to establish a spatial beam element model based on the beam grid method.The antioverturning performance of the radius steel box-concrete composite curved beam bridge was studied,and the vehicle overload degree,support spacing,side-to-span ratio,and curvature radius were used as parameters to analyze the influence of various parameters on the support reaction force and the anti-overturning stability coefficient.The law of influence suggests that increasing the spacing between supports,reducing the side-tospan ratio,and increasing the radius of curvature can all effectively improve the antioverturning performance.