Study On The Practicability Of The New Arch Structure Of Long Span Concrete Filled Steel Tube Arch Bridge

CFST arch bridges have been widely constructed and used in our country,and the application of long-span concrete-filled steel tubular arch bridges is limited because of the weight and stability of arch structures.At present,there are many researches on the main arch ring at home and abroad,such as corrugated steel web and concrete-filled steel tube composite arch.However,there are few data on the arch structure of long span CFST arch bridge.The development of arch structure is closely related to the application of new materials and structures.The new arch structure can give full play to the performance of new materials and structures,and provide a solution for the shortage of long span CFST arch bridge.In this paper,a new type of arch structure is taken as the research object,and a concrete arch bridge(span 260m)is taken as the background project in Zhejiang.The practicability of the new arch structure is studied,and the main work is as follows:1.Collect and sort out the development of new arch structure of long-span concrete filled steel tube arch bridge in China and abroad,summarize the structure form and characteristics of new arch structure,and analyze the existing problems of arch structure.The application of new arch structures at home and abroad is introduced.The structural forms,stress characteristics and calculation theory of new composite columns and composite beams are mainly introduced.2.Research on new type of arch upright post.The traditional arch column(concrete column,steel column)and the new arch column(CFST lattice column),analysis,and analysis of the whole mechanical stability of background engineering with MIDAS results show that the steel column and concrete filled steel tubular lattice column can significantly reduce the column from heavy steel column and concrete filled steel tube columns in effect the static weight and stability are basically the same,in the wind stability of concrete filled steel tubular lattice column is better.3.Study on continuity of bridge system.Arch column with concrete filled steel tubular lattice column,comparative analysis of simply supported continuous structure and traditional structure model(full bridge continuous centroid and part form),the whole mechanical analysis,and stability of the whole bridge with MIDAS.The results show that different bridge road systems of arch stress and stability have little effect,but for the girder has great influence,a new continuous bridge deck system can reduce the peak moment of girder.4.Research of new composite beam.Using a new type of CFST lattice column and continuous girder,comparative analysis of the traditional prestressed concrete T beams and steel-concrete composite beam influence on the structure,the steel and concrete composite beam can reduce the weight of structure 15.6%,significantly improve the stress and deformation of the main arch,is conducive to the development of large span arch bridge to the direction of.5.According to the new arch structure and traditional structure are compared and analyzed in the construction,economy,technology and durability,discuss the practicability of the arch structure based on economic analysis,the results show that compared to the traditional concrete structure and the new structure,when the quality is difficult to control the early production,is also relatively high durability the construction and operation process.And the new structure,high degree of industrialization of materials,less site operations,construction convenience,fast replacement components,better quality,good quality control,durability issues simple and reliable.Considering the increase of labor cost and the decrease of steel price in recent years,the economic advantage of new composite beam will be more and more outstanding.