Study On The Longitudinal Characteristics Of Railway Trains On Bridges

When the train is braked and pulled on the bridge,the tangential force acting on the surface of the rail will be transmitted down to the beam body through the rail structure and to the pier and abutment through the support system.Therefore,the additional force of abutment and pier caused by braking and traction is a key parameter in railway bridge design.In the current code of our country,the additional force of abutment and pier accounts for 10% of the load schema,but the conditions of braking and traction are not distinguished.With the development of China's railway transportation from the traditional mode of mixed passenger and freight railway to the diversification mode of high-speed railway,inter-city railway,mixed passenger and freight railway and heavy-haul railway,the train braking and traction modes have also changed accordingly.Based on this,this paper focuses on the longitudinal action characteristics of trains on bridges.The main research contents and results are as follows:(1)The calculation program is compiled by matlab,the braking force and traction force of different locomotives and vehicles in China are calculated,and the relative data are analyzed and compared.The study has shown that the braking adhesive coefficient and the traction adhesive coefficient of D-Series high-speed trains in China are both obviously less than 0.164,the braking adhesive coefficient of freight trains in China is close to 0.164,and the braking adhesive coefficient and the traction adhesive coefficient of locomotives in China are both obviously greater than 0.164.(2)According to the matching relationship between the types of railway lines and the running trains in our country,the values of braking force and traction force on different railway lines are studied,and a series of recommended longitudinal load coefficients matching the load schema of railway trains are given.(3)The finite element model of bridge-track interaction is established by Ansys,and the longitudinal force transmission integral characteristics of bridge and track and the stress characteristics of piers and abutments under typical working conditions of heavyhaul railway are studied.The main influencing factors are analyzed by parameters,and are compared and demonstrated according to the existing experimental data.The research results show that about 90% of the braking force of the rail surface is transferred from the rail surface to the pier at the lower part of the bridge when the single freight train is braked on the single line,while about 100% of the traction force of the rail surface is transferred from the rail surface to the pier at the lower part of the bridge when the single locomotive is pulled on the single line.The stiffness of pier top line has a major impact on the longitudinal force transmission between bridge and track on the condition of braking and traction,while the bridge span and the rail surface load do not affect the longitudinal force transmission characteristics between bridge and track basically.There are 72 pictures,30 tables and 102 references.