The Research Of Long-span Steel Truss Suspension Bridge New Construction Technology Control

During the development of the suspension bridge theory and practice, erectiontechnology of steel truss suspension bridge in the mountains developed rapidly. First, in thedesign, with theoretical research in-depth, use accurate computational analysis methods, inparticular, a substantial increase in computing power of modern computers and theimprovement of the finite element design software, design safety factor declines from4.0to2.5, the design span is also going across3000m. Secondly, the construction method is goingfrom a single rope lifting to deck crane assembly and the segments fly-over shift and cableslip method, the emergence and development of these methods have greatly improved theconstruction cycle and reduced the costs.Based on piecewise catenaries method, this paper analyzes the elastic elongation leadingto intensity of the set weight changes, weight sag resulting in impairment of elastic modulus,temperature effects and the cable saddle do not coincide at the vertices, and etc., all thesefactors effect and amend on the stress-free length calculation of suspension bridges maincables; put forward the finite element method in the form finding and stress-free lengthcomputational aspects, based on the exact cable element, and work out the correspondingcomputer program. Use Aizhai suspension bridge engineering as an instance; combine themeasured midle-span cable shape and the analysis results based on finite element software, toverify the accuracy of the theoretical calculation and the computer program.Based on the assembly means of the steel truss segment, put forward the spacecalculation method of steel truss error analysis, and analyze the steel truss internal force dueto errors; establish the steel truss space error calculation model, to research the relationshipbetween the maximum error and internal forces, analyzed and compared the steel truss stressin the construction process, base on the consideration of the manufacturing and assemblyerrors.Use the important finite element software MIDAS of suspension bridge calculation, tocalculate construction phase of Aizhai suspension bridge; analyze the main cable shape,hanging cable tension, the anchor span cable force, steel truss rod stress in the construction,confirm the rationality of the sliding method using in the Aizhai steel stiffening truss construction, and analyze the impact of the construction method on the structure stress in theconstruction process.Aim at new construction methods for the mountain suspension bridge--the slidingmethod, analyze the two important parameters: the cable tension and traction, based on thefirst-hand information of the method practice in the Aizhai suspension bridge, find thismethod has many advantages such as the construction cycle fast, safe, reliable, equipmentspace requirements low, and etc, suitable for promotion and application.