Verification of Longitudinal Level Irregularity Suppression Effect at the Structural Boundary by Ballasted Ladder Track

Abstract

The ladder sleeper, which is a type of longitudinal sleeper with long beams in the longitudinal direction of the rail, was developed for the maintenance-labor saving of ballast tracks. In this study, to quantify the load distribution performance of the ladder sleepers at the structural boundary, full-scale model tests were conducted to quantify the vibration transmission reduction effect of the ladder sleepers. Following that, numerical experiments were carried out using a three-dimensional numerical analysis model and it was revealed that the ladder sleeper can reduce the pressure on the sleeper bottom plane by approximately 70% when compared to conventional prestressed concrete sleepers. Furthermore, when laying the ladder sleeper at the structural boundary, it was shown that laying across the structural boundary may be more effective in reducing the pressure on the sleeper bottom plane than laying it in front of the structural boundary. Finally, ladder sleepers were installed on the commercial line and long-term measurements of the longitudinal level irregularity verified the effect of suppressing the longitudinal level irregularity of the ballasted ladder track.

Numerical Investigation of Pre-Stressed Reinforced Concrete Railway Sleeper for High-Speed Application

“…D el 0 is the initial (undamaged) elastic stiffness of the material; whereas d denotes the scalar stiffness degradation variable that is extending from zero (the undamaged state of material) to one (the fully damaged state of material). In the theory of the scalar damage, the stiffness drop is isotropic and considered by the variable of degradation d. By employing the common concepts of continuum damage mechanics, the actual internal force is outlined in Equation (29).…”

“…• increasing the strength of the RC sleepers with the application of different materials such as concrete mixtures or inclusions, geometry, as well as technologies: o steel fibers and graphene oxide [15]; o laminated carbon fiber reinforced polyurethane (L-CFRPU) [16][17][18][19][20]; o ultra-high performance concrete (UHPC) [21], as well as ultra-high performance fibre-reinforced concrete (UHP-FRC) and reactive powder concrete (RPC) [22] to be able to avoid pre-or post-tensioning; o rubber-concrete [23]; o macro synthetic fiber-reinforced concrete (MSFRC) [24]; o metal-matrix composites [25]; o steel fibers with straight and hooked geometry [26]; o palm oil fuel ash as supplement material (instead) of cement [27]; o preplaced aggregate concrete [28]; o ladder tracks [29];…”