Lancang Steel Pipe Reinforced With Concrete Arch Bridge And Reasonable Structure Design, Analysis, And Mechanical Properties

The Lancang River Bridge spanning the Lancang River, with a main span of 342m, is a deck arch bridge reinforced with concrete-filled steel tube, located in Dali-Ruili Railway with a design speed at 140km/h. The stiff skeleton is a steel truss structure, which turns into a single cell and single box section of the main arch structure by filling and outsourcing concrete after swivel construction. The bridge has characteristics of long span and complexity in structure and construction techniques. In order to meet the design and research requirements, the reasonable structural design parameters and the construction procedure on filling and outsourcing concrete are studied, meanwhile, the static characteristics and stabilities during construction and operation stages are analyzed in this thesis. The main research works and results are as follows:1. According to the structure characteristics of the Lancang river arch bridge reinforced with concrete-filled steel tube, the beam-plate spatial analyzing model is constructed by means of large finite element program, compared with the beam-bar spatial analysis model to verify its feasibility and validity.2. Based on the initial design and the finite element analysis results, the problems of initial design are pointed out and the structural parametric analysis are carried on from five aspects:the arch-axis coefficient, the height of arch rid, the thickness of main steel pipe, the elastic modulus value of concrete filled in steel tube and the refinement of simulation of the thickness of plate element of box girder, laying a foundation for structural design optimization and improvement.3. According to the characteristics of complex construction and internal force being decided by construction process, a detailed comparison between filling concrete construction procedure and outsourcing concrete construction procedure is made, proposing the construction procedures of the" first up then down" and the "four ring and different starting point for the bottom and web plate ".4. Based on the results of parametric analysis and construction procedure studies, the structural design is improved combing with the design scheme, also, the static characteristics and stabilities during construction and operation stages are analyzed completely, verifying the rationality of the design.Some proposals of the structural design based on these researches have been adopted, making a certain contribution for the structural design of the bridge.