Research On Longitudinal Interaction Between Girder And Track And Seismic Response Analysis Of Continuous Welded Rail On Arch Bridge

The application of CWR (continuous welded rail) on the bridge has improved the train running performance and reduced the work load of maintenance effectively. The interaction between girder and track (girder-track interaction) is an important research topic in the railway design and it needs to do lots of research work in the design and construction of CWR on various kinds of bridge. Based on the domestic and international researches before, this paper has done some research on the girder-track interaction and related issues of CWR on arch bridge. The main research works are as follows:1. Simplified calculation model for longitudinal force of CWR on three kinds of arch bridgeBased on the principle of girder-track interaction, characteristics of interaction between the bridge structure and the track structure of the railway rach bridge were analyzed, the simplified calculation model for longitudinal force of CWR on deck arch bridge, half-through arch bridge, and through arch bridge were established respectively, and the calculation methods of the parameter selection for the arch rib, column pier, et al in the model have been presented. Beside, a new calculation method for rail bending force was adopted to verify the validity of the model.2. The computer program and its verification for the calculation of longitudinal force of CWR on arch bridgeThe technological process of the computer program for the three kinds of arch bridge is the same. Combining the use of FORTRAN Language and ANSYS software, the general computer program (called ABCWR) for the calculation of longitudinal force of CWR on arch bridge was accomplished, which is able to do the calculation of contractility, bending, braking and breaking conditions of CWR on arch bridge and ordinary bridge. Taking three-span simply supported beam and deck arch bridge as examples, a comparative calculation between the ABCWR and the widely-used program BCWR as well as the track-bridge space coupling model was carried out in order to verify the universality of ABCWR and the validity of the calculation results.3. Study of influence factors on the longitudinal girder-track interaction of CWR on three kinds of arch bridgeABCWR has solved the calculation problems of contractility, bending, braking and breaking forces of CWR on three kinds of arch bridge. The effect of temperature and stiffness of arch rib, column pier or steeve on the contractility forces was researched and the simplified calculation methods for contractility forces on half-through arch bridge and through arch bridge were introduced. The worst operating condition for the calculation of bending force and braking force of CWR on three types of arch bridge was summarized and it suggests that the analysis of bending force of CWR on deck arch bridge should be paid much more attention. Comparative analysis between the formula method and the girder-track interaction method for the calculation of rail breaking made and the girder-track interaction method would be better for all the three types of arch bridge. The influence of span and support layout on the force condition of CWR on deck arch bridge was researched and it suggests that the arch bridge should arrange three-span continuous girder and side spans with fixed bearings at junctional piers as well as some speed locking devices for the force share of piers under the braking operating condition.4. Finite element model for the dynamic calculation of CWR on arch bridge and the research about the influence of the track on the dynamic property of arch bridgeThe finite element model of track-bridge space coupling system for the dynamic calculation of CWR on arch bridge was built. In the model, the longitudinal resistance is ideal elastic-plastic. Taking a deck arch bridge as example, the influence of the secondary dead load and the rail effect on the dynamic properties of arch bridge structure was explored. The analysis shows that the second phase dead load brings down the natural frequency of the whole bridge structure. Because the deformation of arch rib can be restricted by the track longitudinal forces, the longitudinal rigidity of piers and bending natural frequency would be bigger than that in the condition of not considering the restriction of track.5. The influence factor analysis of longitudinal earthquake response on the CWR on arch bridgeBy the use of the finite element dynamic calculation model of track-bridge space coupling system and the nonlinear time-history gradually integral analysis method, detailed analysis of the influence of secondary dead load, frequency spectra characteristics of seismic wave, structure damping ratio, vertical earthquake action, small resistance fasteners, temperature effect of arch rib and the span arrangement on the earthquake response rule of CWR on deck arch bridge was performed. The results show that the arrangement of three-span continuous girder would not make the force condition of CWR on deck arch bridge in earthquake worse, and combining the routine analysis of longitudinal force of CWR, it presents that the arrangement of three-span continuous girder could be even better than the plan using simply supported beam on arch bridge.6. Indoor shaking table model test for longitudinal earthquake response research of ballast CWR on bridgeThe indoor shaking table model test for longitudinal earthquake response research of ballast CWR on bridge was carried out to verify the reasonability of ideal elastic-plastic constitutive model used in the theoretical calculation of longitudinal resistance. The results of the test show that:a) the natural frequency of the test beam gets higher under the longitudinal restraint of rail, which is in accordance with the theoretical analysis, b) the ideal elastic-plastic constitutive model used in the theoretical calculation of longitudinal resistance would get larger stress in the rail than the measured value in the test, but it would underestimate the possible displacement of test beam. c) the calculation results from the revised model can meet the test results well. d) the assumption of ideal elastic-plastic constitutive model used in the theoretical calculation can be accepted in the engineering, because it takes better consideration for the rail stress calculation in the earthquake.