| The mutual additional longitudinal force transmission between continuously welded rails (CWR) and high-speed railway bridges is an important force for high-speed railway bridge. If the force is too great, it may cause the buckling of track or rupture of rail, the running safety of high-speed train is threatened. Moreover, the mutual additional longitudinal force transmission between CWR and high-speed railway bridges is one of control loads for the design of pier and abutment and the foundation of it. Thus the calculation of the additional force is quite important in engineering application.But the mechanics calculation model on this aspect at present is usually plane model. In fact, the bridges, pier and abutment as well as load of the high-speed railway are of strongly spatially mechanics characteristics, the plane mechanics calculation model in this aspect cannot reflect the situations mentioned above effectively, and has its limitations. Moreover, when high-speed train runs or brakes on the railway bridges, rail and bridge will vibrate and thus creates dynamic effect. But the study of the dynamic winding and braking force is almost blank at present.In this paper, based on the achievements of the predecessors, a three-dimensional finite element space mechanical model for calculating the additional longitudinal force transmission between CWR and high-speed railway bridges is established. Furthermore the author makes a detailed study on the additional longitudinal force transmission between CWR and high-speed railway bridges with the model, the main content of this paper are as follows:(1) A static three-dimensional finite element mechanical model for calculating the additional longitudinal force transmission between CWR and high-speed railway bridges is established, examples are given to validate the calculation model.(2) With the static three-dimensional finite element space mechanicalmodel, taking a 10-span 32m simple supported double-track box girder in Qin-Shen passenger special line as an example, the characteristics of additional longitudinal force of rail have been analyzed; and the author also studies the influences of different operation condition, fastener longitudinal resistance , stif&ess of pier and abutment, span of the bridge, layout of fastener, temperature variation of beam, bearing friction resistance, rail type , mechanics model on the mutual interaction between CWR and high-speed railway bridges in detail; Taking the constrain of the sleeper into account, the author establishes a rupture force mechanical calculation model , taking a 10-span 32m simple supported double-track box girder in Qin-Shen passenger special line as an example, the characteristics of longitudinal rupture force of rails when one rail snaps at low temperature are analyzed and the influences of the rail-gap are studied in detail.(3) Taking super-long railway bri%e cross Xin-Yan highway in Qin-Shen passenger special line as an example, the influence of plastic residual deformation, which is caused by cyclic temperature load, on the additional longitudinal force transmission between CWR with the rail expansion adjuster in the middle of the continuous beam and the bridge is analyzed ; The characteristics of additional longitudinal force transmission between CWR without rail expansion adjuster and the bridge are also analyzed; and the influences of different operation condition, train formation, fastener longitudinal resistance , rail type, bearing friction resistance, temperature variation of beam, mechanics model on the mutual interaction between CWR without rail expansion adjuster and the bridge are studied in detail; the longitudinal rupture force characteristics are analyzed and the influence factors of the rail-gap are studied in detail; Based on the study above ,the probability of laying CWR without rail expansion adjuster on the bridge is discussed.(4) A Three-dimensional finite element mechanical model for calculating the dynamic additional longitudinal braking force transmission between CWR and high-speed railway bridges is established; taking a 8-span 32m simplesupported double-track box girder in Qin-Shen passenger special line as an example, the characteristics of dynamic additional longitudinal braking force of rail are analyzed; and the influence of single-track braking, double-track braking with the opposite direction, track longitudinal resistance, train formation, pier height, beam span number ,initial braking velocity on the dynamic effect of rail braking force are studied ;(5) A Three-dimensional finite element vehicle-track-bridge coupling dynamic mechanical model for calculation the winding force is established; taking a 5-span 32m simple supported double-track box girder in Qin-Shen passenger special line as an example, the dynamic additional longitudinal winding force characteristics of rail are analyzed; and the influences of single-track operation ,double-track operation with the opposite direction, track longitudinal resistance, train formation, pier height, beam span number , operation velocity on the dynamic effect of rail winding force are studied.(6) Combining AutoCAD VBA with Ansys secondary development language, a program, in which Three-Dimensional finite element bridge model is automatically generated by the Two-Dimensional cross-sections of the beam, the pier and abutment, is designed, the difficulty of 3D model is greatly reduced, and efficiency and accuracy are obtained.
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