Influence of Track Maintenance on Lateral Resistance of Concrete-Tie Track

2003 ◽  
Vol 1825 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Theodore Sussmann ◽  
Andrew Kish ◽  
Michael Trosino
Keyword(s):  
Critical Level ◽  
Track Structure ◽  
Lateral Stability ◽  
Test Results ◽  
Railroad Track ◽  
Thermal Compression ◽  
Mechanical Stabilization ◽  
Track Maintenance ◽  
Lateral Resistance ◽  
Subsequent Stabilization

Adequate lateral resistance is required to provide the stable track structure necessary for safe rail operations on passenger and freight railroad track. Insufficient lateral resistance, coupled with a large thermal compression force in the rail from high rail temperature, can buckle the track structure. Railroads typically use mechanical stabilization, slow orders, or both, following maintenance operations that disturb the ballast section, such as track surfacing and alignment. Tests were conducted to improve the understanding of lateral resistance variations on concretetie track caused by surfacing and subsequent stabilization or compaction. Factors influencing track stability are summarized, maintenance procedures are described, the single-tie push test is described, and test results are presented. Tests were conducted to evaluate the changes in lateral resistance, from the trafficked, well-consolidated track structure before surfacing and alignment through the laterally weak track structure after surfacing. The influence of stabilization on the lateral resistance of the track structure was evaluated. The tests results indicate that surfacing significantly reduces the lateral stability of the track to a potentially critical level. Mechanical stabilization following surfacing significantly increased the lateral stability of all sections tested.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Developing an Enhanced Short-Range Railroad Track Condition Prediction Model for Optimal Maintenance Scheduling

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Peng Xu ◽  
Chuanjun Jia ◽  
Ye Li ◽  
Quanxin Sun ◽  
Rengkui Liu
Keyword(s):  
Prediction Model ◽  
Short Range ◽  
Prediction Method ◽  
Maintenance Scheduling ◽  
Railroad Track ◽  
Track Geometry ◽  
Track Maintenance ◽  
Track Condition ◽  
Optimal Maintenance ◽  
Process Work

As railroad infrastructure becomes older and older and rail transportation is developing towards higher speed and heavier axle, the risk to safe rail transport and the expenses for railroad maintenance are increasing. The railroad infrastructure deterioration (prediction) model is vital to reducing the risk and the expenses. A short-range track condition prediction method was developed in our previous research on railroad track deterioration analysis. It is intended to provide track maintenance managers with two or three months of track condition in advance to schedule track maintenance activities more smartly. Recent comparison analyses on track geometrical exceptions calculated from track condition measured with track geometry cars and those predicted by the method showed that the method fails to provide reliable condition for some analysis sections. This paper presented the enhancement to the method. One year of track geometry data for the Jiulong-Beijing railroad from track geometry cars was used to conduct error analyses and comparison analyses. Analysis results imply that the enhanced model is robust to make reliable predictions. Our in-process work on applying those predicted conditions for optimal track maintenance scheduling is discussed in brief as well.

The Stress and Stability Analyses of Railroad Tracks

1974 ◽  
Vol 41 (4) ◽  
pp. 841-848 ◽  
Author(s):  
A. D. Kerr
Keyword(s):  
The State ◽  
Track Structure ◽  
Railroad Track ◽  
Stability Analyses ◽  
Railroad Tracks ◽  
The Stability

The paper presents a survey of the state of knowledge in the fields of stress and stability determination of a railroad track. At first, the evolution of the railroad track structure is briefly summarized. This is followed by sections which discuss the development of the methods for the determination of stresses in the rails and ties, and the stability of the railroad track due to constrained thermal expansions.

scholarly journals Behavior of wood beam connection using staples subjected to in-plane moment

2019 ◽  
Vol 258 ◽  
pp. 05008
Author(s):  
Farida Lenggani ◽  
Bambang Suryoatmono
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Solid Wood ◽  
Experimental Results ◽  
Elastic Analysis ◽  
Connection Strength ◽  
Test Results ◽  
Lateral Resistance ◽  
Wood Beams ◽  
Mechanical Fasteners

It is very frequent that solid wood beams need to be connected one to another to obtain a longer beam. In this study, the behavior of solid wood beams connections using plywood sheets as connecting elements and staples as mechanical fasteners were studied experimentally. The experimental results were compared with elastic analyses. Both beam and plywood were made of meranti (shorea). The staple type was MAX 1022J. This study was conducted on two specimens. The first specimen had two rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 40 staples. The second one had three rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 60 staples. From the tests, it can be concluded that each material in the connection, namely wood beam, plywood, and staples, failed. Failure mode of the wood beam was in the form of crack and tear. Failure mode of the plywood was the damage of the plywood directly contacted with the crown of the staples. Failure modes of the staples were flexural yielding. The differences between connection strength obtained from tests and elastic analyses were 8.18% for the first specimen and 0.65% for the second specimen, with the test results were higher than the elastic analyses results. It can be concluded that elastic analysis is quite accurate and conservative to estimate the strength of this type of connection, provided that the lateral resistance of connection with a staple is known.

scholarly journals Track Maintenance Scheduling and Its Interactions With Operations: Dedicated and Mixed High-Speed Rail (HSR) Scenarios

2010 ◽  
Author(s):  
Hamed Pouryousef ◽  
Paulo Teixeira ◽  
Joseph Sussman
Keyword(s):  
Preventive Maintenance ◽  
High Speed ◽  
Maintenance Scheduling ◽  
Track Structure ◽  
Maintenance Planning ◽  
Critical Feature ◽  
High Speed Rail ◽  
Track Maintenance ◽  
Operations And Maintenance ◽  
Technical Specifications

HSRs are a complex system not only in terms of technical specifications, but also with respect to operations and maintenance over the track structure. Also, track structure is basically considered as the most important and costly railway asset. Its maintenance is vital to assure safety and operating practices are also of great importance to assure that a good level of service is provided. Considering track maintenance considerations over a new HSR line, one important and critical feature is the operational regime and the question of whether the line will be operated as mixed (passenger and freight) or dedicated only to passenger traffic. This can influence the maintenance patterns: preventive maintenance planning, maintenances scheduling and assignment issues. This will be different for the dedicated and mixed HSR traffic scenarios. In this research, the main approach is focused on the interactions between track maintenance planning and operational concerns and influences in these two scenarios. With this aim and within the current paper, a model of the preventive maintenance scheduling problem (PMSP) has been selected initially from Budai (2006) and then an upgraded revision of this model (Multi-segment assignment and scheduling of preventive maintenance problem) is introduced. Furthermore, the upgraded model of PMSP has been run over a given HSR line (Tehran-Qom HSR corridor in Iran) based on the comparison between the two scenarios of dedicated HSR and upgraded mixed HSR patterns. The main requirements, similarities and differences between these two scenarios are analyzed based on preventive maintenance scheduling and assignment requisites and interactions over the operating restrictions and considerations such as track possession patterns for maintenance activities. We conclude that decision making between these two scenarios through PMSP modeling are quite complicated and depends on the technical and operational specifications of the given HSR corridor, although some general comments on tradeoffs are possible.

Centrifuge static and dynamic lateral pile behaviour

1987 ◽  
Vol 24 (2) ◽  
pp. 198-207 ◽  
Author(s):  
John M. Ting ◽  
Claudia R. Kauffman ◽  
Maryann Lovicsek
Keyword(s):  
Dynamic Stiffness ◽  
Dynamic Test ◽  
American Petroleum Institute ◽  
Test Results ◽  
Lateral Loads ◽  
Centrifuge Model ◽  
Lateral Resistance ◽  
Data Reduction Method ◽  
Pile Resistance ◽  
Static And Dynamic Loading

The behaviour of a single vertical pile embedded in saturated sand and subjected to cyclic static and dynamic loading is studied using an extensive centrifuge model testing program. A reliable data reduction method allows computation of the dynamic and static cyclic lateral pile resistance–deflection p–y curves. The results are compared with full-scale dynamic test results and oil industry design guidelines.From these comparisons, the centrifuge technique appears to model the dynamic soil–pile system properly. For loadings causing significant nonlinearity, the static stiffness appears to be greater than the dynamic stiffness, while material hysteresis appears about the same in each case. Current American Petroleum Institute guidelines for static cyclic loading appear to overestimate the dynamic lateral resistance for medium dense sands. Key words: centrifuge model, cyclic loads, dynamic response, lateral loads, liquefaction, model tests, pile lateral loads.

Lateral resistance and deflection of flexible piles

1988 ◽  
Vol 25 (3) ◽  
pp. 511-522 ◽  
Author(s):  
G. G. Meyerhof ◽  
V. V. R. N. Sastry ◽  
A. S. Yalcin
Keyword(s):  
Key Words ◽  
Ultimate Load ◽  
Embedment Depth ◽  
Horizontal Load ◽  
Test Results ◽  
Pile Groups ◽  
Single Model ◽  
Lateral Resistance ◽  
Theoretical Analyses ◽  
Lateral Deflections

The ultimate lateral resistance and the groundline lateral deflections under working loads of freestanding single model piles and small pile groups, of various materials and different embedded lengths, subjected to horizontal load have been investigated. The test results of piles of various stiffnesses in sand and clay are compared with theoretical analyses based on the concept of an effective embedment depth in terms of the behaviour of equivalent rigid piles. Key words: clay, piles, displacements, lateral load, lateral resistance, pile stiffness, sand, ultimate load.

Vibration Analysis of Vehicle-Rail System under the Condition of Track Stiffness Irregularity

2013 ◽  
Vol 368-370 ◽  
pp. 1431-1437 ◽  
Author(s):  
Tian Yu Lu ◽  
Zu Jun Yu ◽  
Hong Mei Shi
Keyword(s):  
Frequency Spectrum ◽  
Vibration Frequency ◽  
Vibration Analysis ◽  
High Speed ◽  
Track Structure ◽  
High Speed Train ◽  
Track Maintenance ◽  
Rail System ◽  
Coupling System ◽  
Track Stiffness

The interaction of track structure and high-speed train has greater impact on safe and steady running of the trains. This paper obtained acceleration and frequency spectrum of the train's running vibration in the case of sleeper’s spacing and continuous failure， and continuous and spacing loose tie by establishing the vertical model of vehicle-track coupling system, and analyzed the sleeper failure and loose tie which has a greater impact on the 40-80 Hz vibration frequency of the train, which provided a basis for track maintenance.

Experimental study of interaction and coupling effects in pile groups subjected to torsion

2008 ◽  
Vol 45 (7) ◽  
pp. 1006-1017 ◽  
Author(s):  
L. G. Kong ◽  
L. M. Zhang
Keyword(s):  
Coupling Effect ◽  
Pile Group ◽  
Test Results ◽  
Pile Groups ◽  
Coupling Effects ◽  
Lateral Resistance ◽  
Torsional Resistance ◽  
Pile Interaction ◽  
Group Configuration ◽  
Centrifuge Model Tests

Piles in a pile group subjected to torsion simultaneously mobilize lateral and torsional resistances. Hence, complicated pile–soil–pile interaction effects and load deformation coupling effects occur in the pile group. In this study, a series of centrifuge model tests were carried out to investigate these effects in three-diameter spaced 1 × 2, 2 × 2, and 3 × 3 pile groups subjected to torsion in both loose and dense sands. The test results showed that the effect of horizontal movement of a pile on lateral behaviors of its adjacent piles is significant in 3 × 3 pile groups and such effect varies with group configuration and pile position. The p-multiplier concept can be used to quantify the effect and values for the p-multiplier are suggested. The effect of lateral movement of a pile on the torsional resistances of its adjacent piles and the effect of torsional movement of a pile on the lateral resistances of its adjacent piles were found to be minor in these tests. For an individual pile in a pile group subjected to torsion, the mobilized lateral resistance was found to substantially increase the torsional resistance of the pile. Such a coupling effect is quantified by a coupling coefficient, β, which describes the contribution of subgrade reaction to the increase of torsional shear resistance.

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