Study Of Longitudinal Forec For The Seamless Turnout Scissors Crossing On Ballastless Bridge

Both seamless turnout and continuously welded rail (CWR) track on bridge are key techniques for high speed railway and heavy haul railway to strengthen track structure. The mechanical mechanisms of both seamless turnout and CWR track on bridge are very complex and they have always been the focal points and difficulty points of railway modernization technique research. Because of the restriction of landform or environmental protection, seamless turnout will be unavoidably laid on bridge in newly-built railway or city elevated railway, seamless turnout scissors crossing is one of track equipment made engine block and rolling stock from one route crossover to another route, can shorten station and yard area and length,and abroad application in track traffic of city and railway. In this paper , according to the route of Hainan east-loop the seamless turnout scissors crossing on ballastless bridge,using 60kg/m rail,No.12 fixed frog,and 5.0m between centers of rails scissors crossing structure disposal on continuous.beam,themodeisestablished.by.adopting.finite.elementmethod(FEM). The form of structure and working characteristic are more comlex, the account date of longitudinal force and displacement was not seen,there is no engineering experience of seamless turnout on bridge in China, and the related theory research is also very few. In order to guide the future engineering practice with scientific theory, this paper finished some pioneer theory researches as follows:(1) Aiming at ballastless track, a finite element mechanics model Was established which can calculate the tensile and compressive force and displacement of welded turnout scissors crossing on bridge. In the model, the rails-sleeper-slab-bridge-pier were considered as a system; steel rail and sleeper is simplified to beam elements; ballast bed slab and bridge is solid elements;pier or abutment in fixed bearing was considered as linear spring element; longitudinal ballast resistance, spacer pieces resistance and spacing iron blocks were considered as nonlinear spring element, the model were established by ANSYS.according to Newton-iterative rule to solve.(2) The calculation model of tensile and compressive force anddisplacement of seamless turnout scissors crossing on bridge was applied. The distribution rules. of the tensile and compressive force and displacement of seamless turnout on continuous beam bridge, which mainly comprises longitudinal force and displacements of stock rails, force of the pass-force components, point tongue displacement, longitudinal force and displacements of Pier, the stresses and displacements to track slab and bridge, and the cam and door-style reinforcement bar's forces under the condition of temperature force. Some parameters influencing the tensile and compressive force and displacement of seamless turnout on bridge were studied; such as the algebraic difference between rail temperature and the stress-free temperature, fastener resistance, the length of beam, the stiffness of pier, cam rigidness, different supports arrangement type , different foundation connect type, The reasonable values of parameters were suggested,By analysis, it concludes the cam basement is better than door-style reinforcement bar basement.There search findings of this Paper are important to guide the design, construction and maintaining of seamless turnout on bridge.