Research On Construction Simulation Method Of 600m Grade Steel Pipe Concrete Stiffening Framework Main Arch Ring

Steel tube concrete reinforced skeleton arch bridges have the advantages of good economic performance,good load-bearing performance,and strong load-bearing capacity,and are widely used in mountainous areas of China.Nowadays,one of the main methods for studying this type of arch bridge is finite element simulation.The structure of steel tube concrete reinforced skeleton arch bridge is very complex,and different finite element simulation methods will have a significant impact on the structural stress calculation results.Among them,the main arch ring is the main load-bearing structure of steel tube concrete reinforced skeleton arch bridge,and reasonable finite element simulation is crucial.This article takes a 600 m level steel tube reinforced concrete rigid skeleton arch bridge as the background project,explores and selects a reasonable simulation method for the main arch ring of the steel tube reinforced concrete rigid skeleton arch bridge,and explores and analyzes the sequence scheme of concrete pouring inside the pipe,the sequence scheme of concrete pouring outside the pipe,and the load adjustment scheme with cables.This article mainly conducts research from the following aspects:(1)Two different finite element models were established for the construction stage of the steel tube concrete structure of the background project using the dual element method and the joint section method.The displacement,stress,and stability of the key construction stages of the two models were compared and analyzed.The results showed that the joint section method was more suitable for simulating the steel tube concrete structure.By studying the pouring sequence of the six types of concrete pipes,the final results showed that the upstream and downstream inner steel pipes were poured first,The most reasonable pouring sequence is to pour the upstream and downstream outer steel pipes after pouring.(2)Plate elements and solid elements were used to simulate the outer concrete of a section of the rigid skeleton in the main bridge of the background project.The stress and displacement of the models using the two simulation methods were compared and analyzed.The results showed that the plate element can better simulate the actual stress situation of the outer concrete,and the modeling is simple and the calculation is convenient and fast.Properly dividing the accuracy of the outer concrete plate element can increase the accuracy of the simulation.(3)Three outsourcing concrete pouring sequence schemes were proposed,and the advantages and disadvantages of the three schemes in terms of stress,displacement,and overall stability were compared.The results showed that the pouring sequence from the arch foot to the arch crown was the most suitable outsourcing concrete pouring sequence scheme.A reasonable buckle load adjustment scheme was proposed to address the phenomenon of concrete stress exceeding the limit in the pipe section of the arch foot in Scheme 1,considering the impact of buckle load adjustment on the buckle tower,And analyze the load adjustment results,and all calculation results indicate that the load adjustment effect is good.The research results of this article will provide certain reference value for the finite element simulation and construction process optimization of future 600 m grade steel tube concrete reinforced skeleton arch bridges.