Construction Process Analysis Of Super-long Distance Incremental Launching For The Steel Box Girder Of Long Span Arch Bridge With High Piers

Based on an under-construction long-span arch bridge,combined the related literature and the design data,the local force,displacement,stability analysis and other key technical problems of the steel box girder in the incremental launching construction process are systematically studied in this thesis.Firstly,the development status of the incremental launching method around the world is introduced;the different incremental launching methods and their main technical characteristics,temporary facilities and points for attention are expounded.Based on the actual engineering background,the classical analytical method is used to calculate the stress of the nose-main girder in incremental launching construction.The reasonable analytical solution for nose girder parameters is obtained and then verified by numerical simulation method.The calculation results can provide reference for determining the design scheme of the nose girder.In the finite element software,the model of steel box girder and the substructure in the incremental launching process is established;the internal force,stress,deformation of the steel box girder,the support reaction and the displacement of the piers on the arch are analyzed;the influence of pier top displacement on the steel box girder's internal force is studied;the buckling stability of the main bridge under dangerous cases during the incremental launching process is further analyzed,and the bridge structure security is also assessed.The local model of steel box girder in dangerous condition during incremental launching process is established,and the stress distribution law of top and bottom deck,web,and stiffening rib of box girder under the worst condition is studied.The possible causes and consequences of lateral displacement of steel box girder are analyzed,and the influence of the lateral displacement on its own stress distribution is also analyzed.