Evaluating tie support at railway bridge transitions

Wilk, Stephen T.; Stark, Timothy D.; Rose, Jerry G.

doi:10.1177/0954409715596192

Cited by 18 publications

(12 citation statements)

References 16 publications

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“…In addition to mechanical loading and performance aspects, such as the structural rigidity and contact force below crosstie, dynamic behavior trends including vibration velocity and acceleration are used for track evaluation. Excessive vibrations usually indicate undesired track conditions such as the effects of a hanging crosstie, ballast non-uniform support conditions, or ballast fouling ( 16, 31–35 ). Investigating crosstie vibration velocity can bring insights on the implications of ballast degradation to track performance.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Effect of Ballast Degradation on Track Dynamic Behavior Using Discrete Element Modeling

Liu

Feng

Tutumluer

2022

Transportation Research Record: Journal of the Transportation R

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Ballast degradation refers to the traffic use of in-service track when aggregate particles become smaller in size and fines are generated because of particle breakage and abrasion to cause geometry defects and influence the serviceability of ballasted track affecting train operations. To evaluate effects of ballast degradation on track substructure maintenance needs, single crosstie models were developed to simulate new and degraded ballast behavior under train loading. Particle size distributions and shape properties of the new and degraded ballast materials studied were adopted from previous laboratory tests conducted at the University of Illinois, U.S. Crosstie vibrations, ballast particle contact force distributions and particle rotations, and localized contact force chain networks were compared among different single crosstie models incorporating new and degraded ballast. The following key observations were made based on the simulation results: (1) crosstie on degraded ballast exhibits larger vibrations and more inconsistent vibration patterns; (2) degraded ballast shows a higher number of localized force chains with more particle contacts while the characteristic trend observed for new ballast is the presence of more symmetric force chain networks, which might be attributed to the new ballast layer’s uniform gradation and good interlock; (3) average normal contact forces are distributed more uniformly in new ballast in both horizontal and vertical directions as opposed to these forces concentrated more in vertical direction in degraded ballast; and (4) more ballast particles experience large rotations in degraded ballast and the related impact zone, which encloses all particles with large rotations, is also broader and deeper.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Effect of Ballast Degradation on Track Dynamic Behavior Using Discrete Element Modeling

Liu

Feng

Tutumluer

2022

Transportation Research Record: Journal of the Transportation R

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“…This pivoting generates an increase in impact loading on the ballast, which increases ballast degradation. 5,24,29–31 As a consequence, the track deteriorates and continuing maintenance is required.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Dynamic behaviour of transition zones in soft soils during regular train traffic

Coelho

Priest

Hölscher

2017

Proceedings of the Institution of Mechanical Engineers, Part F:

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Transition zones in railway tracks are of importance for infrastructure managers, due to the high maintenance required to maintain appropriate track geometry. To improve our understanding of the performance of transition zones, a research program was conducted in The Netherlands, in which a transition zone was extensively monitored during regular train traffic. This paper presents some of the results from the monitoring of this transition zone. The results highlight the poor performance of this transition zone compared to its expected design performance. The track was found to be hanging over the transition zone, exhibiting a rocking motion about a culvert. Track stiffness was found to reduce linearly with increasing train speed. The implications on the design of transition zones are discussed, with recommendations made.

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“…This change was found to be related to the rough site areas that exhibited settlement-related track geometry variability because of fouled ballast. In these areas, the effect of fouled ballast was manifested through tie settlement or the development of tie-ballast gaps that can lead to load redistribution in the track structure (11). The contact deflection was found to not significantly differ between the rough and smooth site (Figure 2 and Table 1).…”

Section: Track Load-deflection Behaviormentioning

confidence: 98%

Track Support Measurements for Improved Resiliency of Railway Infrastructure

Sussmann

Stark

Wilk

et al. 2017

Transportation Research Record: Journal of the Transportation R

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Track support is necessary for reliable, resilient railroad track infrastructure. Ability to recover quickly from adversity is a hallmark of the railway industry, and ability to rapidly restore track to service is a main element contributing to resilience of rail service. Poor track support conditions can increase dynamic and impact loading on track superstructure components that can accelerate deterioration of track components, potentially inhibiting the resilience of railroad track. As track components deteriorate or material properties continue to degrade in an area, affected ties become poorly supported and shed their load to better-supported ties. Various problems develop owing to increased tie load, rail stress, and ballast stress, leading to ballast degradation and track or tie vibrations. These problems can be avoided if proper track support is uniformly provided so that no area is overstressed. Several measurement techniques are discussed for evaluating track support: modulus and transient displacements, including track deflection techniques, video cameras, accelerometers, spectral analysis of surface waves for assessment of sublayer moduli, and falling weight deflectometer for deflection and basin analyses. These measurement techniques are compared and contrasted, are illustrated by using a track bearing capacity example, and are demonstrated as useful in assessing tie and track support problems with the goal of improving inspection and maintenance at problem locations. Data from these tests can be useful in designing track and maintenance plans to avoid track support failures, a necessary step to ensure track infrastructure resiliency.

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Evaluating tie support at railway bridge transitions

Cited by 18 publications

References 16 publications

Effect of Ballast Degradation on Track Dynamic Behavior Using Discrete Element Modeling

Effect of Ballast Degradation on Track Dynamic Behavior Using Discrete Element Modeling

Dynamic behaviour of transition zones in soft soils during regular train traffic

Track Support Measurements for Improved Resiliency of Railway Infrastructure

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