Study On Construction Technology And Mechanical Characteristics Of Steel Truss Girder Under Overall Transverse Sliding

As a new form of bridge facilities,steel truss girder is more and more widely used.It has many advantages,such as large span capacity,easy installation,light weight,beautiful appearance,and so on.It plays an important role in bridge engineering.Taking a 132M steel truss beam of a high-speed railway bridge across existing high-speed railway and expressway as an example,this paper studies the construction technology and structural mechanics characteristics of the steel truss beam.(1)Integral Transverse Construction Technology of Steel Truss GirderThis paper expounds in detail the construction technology of the overall scheme of transverse movement of steel truss beams,including the assembling of supports,installation and dismantling of slideway beams,dragging and monitoring methods of steel truss beams in the course of transverse movement,and puts forward the key control measures of transverse movement construction of steel truss beams.(2)Structural and mechanical analysis of steel truss beam splicing construction processComparing the existing construction scheme with the original one,the advantages and disadvantages of different construction schemes are summarized.By using MIDAS/CIVIL finite element software,a three-dimensional spatial model of steel truss beam is established to simulate the assembly and slip construction of steel truss beam.The structural spatial stress of main truss and assembly beam during splicing process is calculated,and the mechanical properties of main truss and connection system during slip process are analyzed.The results show that the relative displacement difference between supporting points is controlled by the relative displacement difference during construction,and the relative displacement difference between supporting points during construction should not be greater than 60 mm.(3)Analysis of mechanical characteristics of temporary pier auxiliary facilitiesBased on structural mechanics theory and finite element method,the strength and stability of column sections of 83 piers and steel pipe temporary piers,and the strength and stiffness changes of pier top distributor beams and slideway beams during the construction of steel truss beams are studied.The results show that the stability of steel pipe temporary pier has little change during the sliding construction of steel truss beam,and the strength,stiffness and stability of 83 piers meet the design requirements.When the steel truss beam is transversely moved to 1/2 stage,the stress and vertical deformation of the mid-span section of the slideway beam are the largest.