Research On Key Technology Of Arch Rib Construction Of (100+196+100)m Concrete-filled Steel Tube Arch Beam Composite Bridge

Concrete-filled steel tube arch girder composite bridge is the most commonly used type of concrete filled steel tube arch bridge.Because of its high safety,strong crossing ability and unique structure,composite arch girder bridge is widely used in bridge construction in the world,especially in the construction of high-speed railway bridge.The structural stiffness of concrete-filled steel tube arch beam composite bridge during arch rib construction is composed of phases,and there are many arch rib arch modes.Therefore,the comparative analysis of the stress and deformation of various structures of this type of bridge arch rib under different arch modes,the comparison and selection of arch modes and the study of arch rib concrete filling sequence can provide important theoretical basis for bridge construction.This paper takes a(100+196+100)m concrete-filled steel tube arch girder composite bridge as the research object.Combining theoretical calculation and numerical simulation,the construction scheme of arch rib and the sequence of concrete filling in the pipe are studied,and the construction scheme of arch rib is compared and selected.The main work contents and achievements are as follows:(1)The structural form,classification,characteristics and calculation theory of concrete-filled steel tube arch girder composite bridge are introduced.This paper summarizes the research status and shortcomings of concrete filled steel tube arch girder composite bridge on arch rib arch forming method,selection method of construction scheme and concrete filling in pipes.(2)Based on Midas Civil,the finite element model of the bridge was established and the stress and deformation of the arch ribs and main beams in the construction process of the arch rib bracket and the vertical rotation method was simulated and the differences of different arch forming modes were studied.(3)The selection method of common construction schemes is introduced.Starting from the mechanical characteristics of various structures under different arch modes,a more reasonable arch mode of the bridge is obtained by comparing.Based on the analytic hierarchy process(AHP)which comprehensively considers the five factors,the calculation process of constructing the judgment matrix and synthesis matrix,solving the feature vector and checking the consistency of the judgment matrix is expounded.It is concluded that it is more reasonable to use the vertical rotation method for the construction of this bridge.(4)For the first time,the interval triangle fuzzy multi-attribute decision-making method is applied to the comparison selection of bridge construction scheme,and the comparison study is carried out on the construction scheme of the arch rib relying on the project.The basic theory and calculation procedure of interval triangular fuzzy multi-attribute decision making method are described.Through the calculation of interval triangle fuzzy decision matrix,normalized interval triangle fuzzy decision matrix,grey correlation coefficient,grey correlation degree,possibility degree matrix and ranking vector,it is concluded that the construction of the vertical rotating body method is more reasonable than that of the support method.And the comparison results are compared with the existing conclusions to verify the accuracy and applicability of the comparison method.(5)A double unit model was selected to study the infusing sequence of steel pipe arch rib concrete from Jihete Bridge.Seven infusing sequences were proposed and the stress and deformation of the arch ribs were compared.The results showed that step 6: infusing the lower chord first,then the upper chord and finally the web was the most reasonable.