Study On The Track System Of The Large-span Bridge Expansion Joint

With the rapid development of the bridge transportation industry in our country and the constant improvement of bridge construction technology, an increasing number of large-span bridges begin to enter the historical stage. And with the span of the bridge increasing, the track laying on larger bridge expansion joints has become an inevitable problem. In order to solve the problem of the track laying on large bridge joints, this paper is based on the application of the optimally designed longitudinal sleeper on the large-span bridge expansion joint as the background to study the theory of the track system of the large-span bridge expansion joint, which has put forward alternatives for track laying on large-span bridge expansion joint. At the same time, with the aid of the Visual Fortran programming and ANSYS14.0, the finite element model for orbital mechanics is established to verify.it is feasible to establish the track system of large-span bridge expansion joint under the action of train load. The main work accomplished in this paper are as follows:(1) A large number of related literature both at home and abroad have been referred to; Inspired by the devices of the bridge expansion joint in highway and railway, the structure characteristics of longitudinal sleeper are seriously analyzed, which provides the theory and data support for application of longitudinal sleeper on the bridge expansion joint.(2) The optimally designed longitudinal sleeper with the length of 5785 mm, width of 2116 mm and height of 200 mm is finally determined as the research object to provide a track laying scheme for large-span bridges whose bridge expansion joint is of the size of 1200 mm, and propose a new design idea for laying track scheme for the large or super-large bridge whose bridge expansion joint is over the size of 1200 mm.(3) Combined with the orbital mechanics model on expansion joint and based on a certain mechanics assumption, double composite beam model is established; Under the analysis by Visual Fortran program, calculate the internal force and the vertical displacement of the longitudinal sleeper.(4) Use the ANSYS to establish the finite element model of the orbit for a large-span bridge expansion joint; Based on the three kinds of incentive models named static load, moving mass and moving load, the improved incentive model is established which is more close to the actual operation situation; Make the dynamics calculation of the large-span bridge expansion joint track system in the improved incentive model;Figure out the internal force of the structure and the vertical displacement of longitudinal sleeper when expansion joints completely unfold or the sleepers meet with each other on expansion joints; Verify the feasibility of longitudinal extension of the track system of the large-span bridge under the temperature load.(5) It proves the relative accuracy of the results of the simulation through the theoretical calculation and the results of the ANSYS simulation in the incentive model;The results show that the track system of the large-span bridge expansion joint can be retractable and satisfies the requirement of orbital smoothness and structural safety.