钢管混凝土拱桥封铰混凝土浇筑时机对比研究OA

The pouring timing of sealing hinge concrete for concrete-filled steel tube arch bridges directly affects the construction duration and the stress state of arch ribs.To clarify the structural response differences at different pouring timings,the Beiliuhe Extra-large Bridge on the Pingxi-Cenxi Expressway in Guangxi Province was taken as the engineering background in this paper.A finite element model was established using Midas Civil,and the following four pouring timings of sealing hinge concrete were comparatively analyzed:immediately after the butt welding of sealing hinge steel pipes;after the closure of arch ribs and before the pouring of concrete inside pipes;after the pouring of concrete inside pipes and before the lifting of lattice girders;after the pouring of wet joints of the bridge deck and before the application of the second-phase dead load.Through the finite element simulation analysis of the whole construction process,the internal forces,stresses,and deformations of key parts under the four timings,as well as the deformations at the completed bridge stage,were compared.The results indicate that all four pouring timings of sealing hinge concrete are feasible;from the perspective of the strength and stability of chord pipes at the arch feet,timing 4(pouring the sealing hinge concrete after the pouring of wet joints of the bridge deck)is the most favorable.As long as there is no conflict in working surfaces,the pouring of sealing hinge concrete can be carried out at any construction stage after the butt welding of sealing hinge steel pipes.The reason for the above phenomenon is that the arch rib axis of this bridge is a catenary curve,which is mainly subjected to compression with a small bending moment under the dead load state.The research results provide a basis for selecting the pouring timing of sealing hinge concrete for this bridge and can serve as a reference for related construction of similar bridges.