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In railway tracks, additional stresses occur in rails due to interaction between the rail and the bridge superstructure, which is a phenomenon known as track–bridge interaction (TBI). The additional rail stresses (ARSs) develop primarily as a result of temperature effect, vertical bending of bridge superstructure, and braking/acceleration of trains traveling over the bridge. One of the major parameters affecting the TBI response is the behavior of interface elements simulating the coupling between the bridge superstructure and the rail. In TBI analysis this coupling is defined by the so-called longitudinal resistance-displacement curves (RDCs). The present study deals with the longitudinal aspect of TBI though a numerical investigation. The numerical modeling approach was verified with available analytical solutions and data obtained from bridge monitoring. The primary interest was to illustrate how sensitive the TBI response is to changes in RDCs with both separate and sequential analysis approaches, which has not been investigated thoroughly earlier. The parametric study was extended to investigate the effects of expansion length and substructure stiffness, in addition to RDC type. For simply supported precast girder bridges, RDCs that are experimentally proven specific to ballastless railway bridges can be used as an economic alternative to those specified by provisions. [ABSTRACT FROM AUTHOR]

Highlights: The paper concerns the possibility of using an innovative railway rail structure in a contactless track: The correct operation of CWR track, due to the occurrence of additional thermal stresses with a value dependent on changes in rail temperature, requires a systematic diagnosis of its condition; The paper presents the research of longitudinal force load tests for a classic rail and for two cases of an innovative railway rail solution. The research presented in the paper shows that: The proposed proprietary design of the rail used for the railroad track can enable the reduction in the longitudinal force occurring as a result of high ambient temperatures; The use of an innovative rail conception will allow for less steel consumption, which means less emissions into the atmosphere during its production (lower carbon footprint). This paper presents the concept of a modified 60E1 rail dedicated to continuous welded rail (CWR) track. The presented solution is the subject of a patent application by the authors of the publication. The paper describes problems associated with the operation of CWR track and the phenomena of so-called "rail stressing", i.e., stresses created in the rail due to thermal shrinkage that, in extreme cases, can lead to the buckling of the rail track. Simulation calculations of longitudinal track loads to represent the occurrence of thermal force as a result of the occurrence of high air temperatures were carried out for the constructed conventional model of the railroad track as well as the track with the proposed solutions. A discussion of the simulation results is presented, indicating the possibility for the wider application of both varieties of modified rail. [ABSTRACT FROM AUTHOR]

This paper presents the concept of a modified 60E1 rail dedicated to continuous welded rail (CWR) track. The presented solution is the subject of a patent application by the authors of the publication. The paper describes problems associated with the operation of CWR track and the phenomena of so-called “rail stressing”, i.e., stresses created in the rail due to thermal shrinkage that, in extreme cases, can lead to the buckling of the rail track. Simulation calculations of longitudinal track loads to represent the occurrence of thermal force as a result of the occurrence of high air temperatures were carried out for the constructed conventional model of the railroad track as well as the track with the proposed solutions. A discussion of the simulation results is presented, indicating the possibility for the wider application of both varieties of modified rail.

Track longitudinal resistance is defined as the resistance generated by sleeper-ballast and rail-sleeper interactions against the imposing forces, which cause longitudinal displacement. This component is one of the important indicators of the continuously welded rail (CWR) track's stability and lateral resistance against buckling. In this paper, the track longitudinal resistance (TLR) and track longitudinal stiffness (TLS) have been investigated to determine the contribution of the fastening system and sleeper in TLR and TLS through laboratory tests and a numerical model. A track panel with one to eight sleepers fastened with 100, 80 and 60 Nm prestressed torqe-force applied to fastening screws was loaded. The average contribution of the sleepers in TLR in the case with a rail-pad for 100 and 60 Nm torque-forces is approximately 30% and 75%, respectively, and the average contribution of the fastening system in the same state is approximately 70% and 25%, respectively. [ABSTRACT FROM AUTHOR]

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The value of the rail-breaking force in the TB10015-2012 Code for Design of Railway Continuous Welded Rail is conservative and sometimes restricts the design of the bridge. This paper takes the 16, 20, 24, 32 m and 40 m simply supported beams commonly used in railway as research objects, and establishes the three-dimensional finite element calculation model of the rail-bridge-beam abutment. The established model is used to calculate the rail breaking force of the abutment under the conditions of four rail breaking and single rail breaking in view of the ballastless and ballasted tracks, and different stiffness of simply supported beam abutments. On this basis, the correction coefficient of the breaking force calculation formula is proposed. The research results show that the correction coefficient of 16m and 40m simply supported beams is respectively 0. 98 and 0. 8 times of the standard value, the longer the simply supported beam span, the smaller the correction coefficient; the correction coefficient of ballastless track and ballasted track for the 40m span simply supported beam is respectively 0.8 and 0.9 times of the standard value; for simply supported beams of the same span, the correction coefficient of ballastless track is smaller than that of ballasted track. [ABSTRACT FROM AUTHOR]

For an open-deck steel plate girder railway bridge with rail joints, frequent damage to the bridge members and a high level of noise and vibration occur. By installing continuous welded rail (CWR) to the bridge, it is possible to reduce the noise and impact force of the bridge. However, current girder–sleeper fasteners have low lateral resistance in nature and track buckling can occur when CWR is used on such a bridge. Therefore, a new girder-sleeper fastener with proper lateral resistance to prevent CWR track buckling is needed. In this study, the lateral resistance requirements of a girder-sleeper fastener are investigated through a series of finite element (FE) analyses and parametric study. The effect of peak lateral resistance of the fastener, curve radius, girder length, and lateral displacement of girder are examined. From the analysis results, the peak lateral resistance criterion of the girder–sleeper fastener is proposed for the design of a new fastener for CWR tracks on an open-deck steel plate girder bridge. [ABSTRACT FROM AUTHOR]

In recent years, joint types in railway superstructure have shifted to continuous welded rails (CWRs), which can be constructed by various welding techniques to form uninterrupted rails several kilometres long. Because of the numerous advantages of this method, CWR systems are highly preferred today for the construction of new railway lines. The increase in the number of trains in operation is inducing fatigue damages, linking to life‐threatening risks in the rails as well as in trains' wheels and axles. In this study, CWR specimens formed by the flash butt‐welding process are investigated. Specimens extracted from rail sections are subjected to four‐point bending fatigue tests to establish S–N curves under various loading levels. The surfaces of those specimens which fail are then investigated in detail in order to determine the initiation points of the failures. The findings provide experimental data on the dynamic life cycle of CWR and identify the failure mechanism of the CWR system. [ABSTRACT FROM AUTHOR]

For an open-deck steel plate girder railway bridge with rail joints, frequent damage to the bridge members and a high level of noise and vibration occur. By installing continuous welded rail (CWR) to the bridge, it is possible to reduce the noise and impact force of the bridge. However, current girder–sleeper fasteners have low lateral resistance in nature and track buckling can occur when CWR is used on such a bridge. Therefore, a new girder-sleeper fastener with proper lateral resistance to prevent CWR track buckling is needed. In this study, the lateral resistance requirements of a girder-sleeper fastener are investigated through a series of finite element (FE) analyses and parametric study. The effect of peak lateral resistance of the fastener, curve radius, girder length, and lateral displacement of girder are examined. From the analysis results, the peak lateral resistance criterion of the girder–sleeper fastener is proposed for the design of a new fastener for CWR tracks on an open-deck steel plate girder bridge.

Abstract Additional axial stresses in the rail are developed due to the influence of the track-bridge interaction (TBI) when the CWR (Continuous Welded Rail) track is used in the railway bridge. This is the main reason of the length limitation of railway bridge and an increase in the construction cost. Also, the track-bridge interaction analysis should be performed in order to examine the influence of track-bridge interaction. Several standards specifies analysis methods and limit values for TBI to guarantee the safety design of railway track. However, the interaction effects are not fully understood yet due to the uncertainty of ballasted track. Thus, the interaction effects should be investigated and verified based on the field test results. In this paper, the measurement and analysis method for the track-bridge interaction was proposed. For this, the measurement system was developed considering the parameters causing the track-bridge interaction, and the track-bridge interaction response caused by temperature change was measured and analyzed. From the results, the track-bridge interaction phenomenon can be fully analyzed and quantified through the measurement system presented in this study. In addition, finite element analysis was conducted and the results were compared with the measured track-bridge interaction response. Highlights • The TBI(Track-Bridge Interaction) effects is not fully understood yet due to the uncertainty of ballasted track. • Field measurement system and the analysis method to investigate the track-bridge interaction behavior was proposed. • The track-bridge interaction response caused by temperature change was quantified through the developed measurement system. • Finite element analysis was conducted and the results were compared with the measured track-bridge interaction response. [ABSTRACT FROM AUTHOR]

The crucial differences between conventional rail with split-type connectors and continuous welded rails are axial stress in the longitudinal direction and stability, as well as other issues generated under the influence of loading effects. Longitudinal stresses generated in continuously welded rails on railway bridges are strongly influenced by the nonlinear behavior of the supporting system comprising sleepers and ballasts. Thus, the track structure interaction cannot be neglected. The rail-support system mentioned above has properties of non-uniform material distribution and uncertainty of construction quality. The linear elastic hypothesis therefore cannot correctly evaluate the stress distribution within the rails. The aim of this study is to apply the nonlinear finite element method using the nonlinear coupling interface between the track and structural model and to illustrate the welded rail behavior under the loading effect and uncertain factors of the ballast. Numerical results of nonlinear finite analysis with a three-dimensional solid and frame element model are presented for a typical track-bridge system. A composite plate girder, modeled by solid and shell elements, is also analyzed to consider the behavior of the welded rail. The analysis result showed buckling under the independent calculations of load cases, including 'temperature change', 'bending of the supporting structure', and 'braking' of the railway vehicle. A parametric study of the load combination method and the loading sequence is also included in this analysis. [ABSTRACT FROM AUTHOR]

Due to increased traffic growth and inadequate public transport, the rapid mass transportation system has been started in India. The metro rail transit system is one of the widely used mass transportation systems. This paper discusses the behavior of the system in terms of forces and displacement due to interaction between Continuous Welded Rail (CWR) and the structure under longitudinal forces like braking/traction and temperature loading. The paper illustrates the concept and methodology used for Rail Structure Interaction (RSI) of bridges and modeling of RSI problem using MIDAS Civil 2014. The software results are compared with test case problems given in the UIC Code 774-3R. The paper justifies the need for RSI analysis for bridges, which is used to determine the additional stresses developed in the rails as well as superstructure and substructure of the bridges due to use of continuous welded rails. [ABSTRACT FROM AUTHOR]