The Calculation of the Supporting Stress of Track Plate in Ballastless High-Speed Rail Structure

2011 ◽  
Vol 97-98 ◽  
pp. 3-9
Author(s):  
Yang Wang ◽  
Quan Mei Gong ◽  
Mei Fang Li
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Design Theory ◽  
Moving Load ◽  
Structure Design ◽  
Track Structure ◽  
Beam Model ◽  
High Speed Rail ◽  
Slab Track ◽  
Ballastless Track

The slab track is a new sort of track structure, which has been widely used in high-speed rail and special line for passenger. However, the ballastless track structure design theory is still not perfect and can not meet the requirements of current high-speed rail and passenger line ballastless track. In this paper, composite beam method is used to calculate the deflection of the track plate and in this way the vertical supporting stress distribution of the track plate can be gotten which set a basis for the follow-up study of the dynamic stress distribution in the subgrade. Slab track plate’s bearing stress under moving load is analyzed through Matlab program. By calculation and analysis, it is found that the deflection of track plate and the rail in the double-point-supported finite beam model refers to the rate of spring coefficient of the fastener and the mortar.The supporting stress of the rail plate is inversely proportional to the supporting stress of the rail. The two boundary conditions of that model ,namely, setting the end of the model in the seams of the track plate or not , have little effect on the results. We can use the supporting stress of the track plates on state 1to get the distribution of the supporting stress in the track plate when bogies pass. Also, when the dynamic load magnification factor is 1.2, the track plate supporting stress of CRST I & CRST II-plate non-ballasted structure is around 40kPa.

scholarly journals Railway superstructure for high-speed rails

2021 ◽  
Vol 31 ◽  
pp. 53-57
Author(s):  
Lukáš Týfa ◽  
Jan Kruntorád ◽  
Ondřej Tomaschko
Keyword(s):  
Research And Development ◽  
High Speed ◽  
Track Structure ◽  
High Speed Rail ◽  
Track Geometry ◽  
Advantages And Disadvantages ◽  
Ballastless Track ◽  
Present Experience ◽  
Long Time

The construction of the track is solved as a conventional (with track ballast) or as a ballastless track (without track ballast). When deciding on the choice of the most suitable track design for high-speed rail, it is necessary to emphasize that with increasing line speed, the requirements for the quality of the track geometry increase, including the size of the deviations of individual geometric parameters of the track from the projected values. When assessing the choice of track structure – especially for high-speed rails – it is therefore necessary and correct to assess the total costs (investment and operational) for a sufficiently long time. DB Netz AG’s present experience with a ballastless track since its first implementation in 1972 in Rheda station, for almost 50 years, shows that the required lifetime of 60 years has its real justification. In addition, current research and development in the field of ballastless track is moving towards extending the life of ballastless track well beyond this limit. The paper is focused on the comparison a ballasted and ballastless track construction. It deals in more detail with evaluation of the advantages and disadvantages of a ballastless track construction. The main objective is to assess the use of ballastless track structure for the construction of high-speed lines.

Experimental Study on Vertical Stiffness of WJ-8 Fastener for High-Speed Railway

2015 ◽  
Vol 723 ◽  
pp. 100-103 ◽  
Author(s):  
Can Liu ◽  
Zhi Ping Zeng ◽  
Jia Yu Yuan ◽  
Bin Wu ◽  
Kun Teng Zhu
Keyword(s):  
High Speed ◽  
Plate Theory ◽  
Vertical Displacement ◽  
Track Structure ◽  
Static Stiffness ◽  
Analysis Model ◽  
Element Analysis ◽  
Vertical Stiffness ◽  
Slab Track ◽  
Ballastless Track

The rail vertical displacement of CRTSII slab track structure under vertical static loads was analyzed in this paper by using 1:1 full-scale track model, based on which the WJ-8 fastener vertical static stiffness was calculated, and the rationality of the fastener vertical stiffness values and the relationship between the values and load were studied. According to the beam-plate theory and beam-solid theory for slab ballastless track, a finite element analysis model of CRTSII slab track structure was established. The rail vertical displacement under the same case as test was calculated by using the measured fastener vertical stiffness value. The rationality of the method for testing and the fastener vertical static stiffness is verified through comparing the calculated values with experimental ones.

scholarly journals Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2876
Author(s):  
Yingying Zhang ◽  
Lingyu Zhou ◽  
Akim D. Mahunon ◽  
Guangchao Zhang ◽  
Xiusheng Peng ◽  
...  
Keyword(s):  
High Speed ◽  
Thermal Loading ◽  
Mechanical Performance ◽  
Track Structure ◽  
Box Girder ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Track System ◽  
Girder Bridge ◽  
Track Slab

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

scholarly journals Deformation Law and Control Limit of CRTSIII Slab Track under Subgrade Frost Heave

2021 ◽  
Vol 11 (8) ◽  
pp. 3520
Author(s):  
Xiaopei Cai ◽  
Qian Zhang ◽  
Yanrong Zhang ◽  
Qihao Wang ◽  
Bicheng Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Base Plate ◽  
Element Model ◽  
Middle Part ◽  
Railway Track ◽  
Frost Heave ◽  
Track Structure ◽  
Slab Track ◽  
Plastic Damage ◽  
Track Irregularity

In order to find out the influence of subgrade frost heave on the deformation of track structure and track irregularity of high-speed railways, a nonlinear damage finite element model for China Railway Track System III (CRTSIII) slab track subgrade was established based on the constitutive theory of concrete plastic damage. The analysis of track structure deformation under different subgrade frost heave conditions was focused on, and amplitude the limit of subgrade frost heave was put forward according to the characteristics of interlayer seams. This work is expected to provide guidance for design and construction. Subgrade frost heave was found to cause cosine-type irregularities of rails and the interlayer seams in the track structure, and the displacement in lower foundation mapping to rail surfaces increased. When frost heave occured in the middle part of the track slab, it caused the greatest amount of track irregularity, resulting in a longer and higher seam. Along with the increase in frost heave amplitude, the length of the seam increased linearly whilst its height increased nonlinearly. When the frost heave amplitude reached 35 mm, cracks appeared along the transverse direction of the upper concrete surface on the base plate due to plastic damage; consequently, the base plate started to bend, which reduced interlayer seams. Based on the critical value of track structures’ interlayer seams under different frost heave conditions, four control limits of subgrade frost heave at different levels of frost heave amplitude/wavelength were obtained.

Narrowing longitudinally coupled prefabricated slab track maintenance duration with field data analysis of slab deformation under high temperature

2021 ◽  
pp. 095440972098626
Author(s):  
Zai-Wei Li ◽  
Xiao-Zhou Liu ◽  
Hong-Yao Lu ◽  
Yue-Lei He
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Ride Comfort ◽  
Cost Effective ◽  
Periodic Variation ◽  
Longitudinal Force ◽  
Distribution Analysis ◽  
High Speed Rail ◽  
Track Maintenance ◽  
Slab Track

The deformation of longitudinally coupled prefabricated slab track (LCPST) due to high temperature may lead to a reduction in ride comfort and safety in high-speed rail (HSR) operation. It is thus critical to understand and track the development of such defects. This study develops an online monitoring system to analyze LCPST deformation at different slab depths under various temperatures. The trackside system, powered by solar energy with STM8L core that is ultra-low in energy consumption, is used to collect data of LCPST deformation and temperature level uninterruptedly. With canonical correlation analysis, it is found that LCPST deformation presents similar periodic variation to yearly temperature fluctuation and large longitudinal force may be generated as heat accumulates in summer, thereby causing track defects. Then the distribution of temperature and deformation data is categorized based on fuzzy c-means clustering. Through the distribution analysis, it is suggested that slab inspection can be shortened to 6 hours, i.e. from 10:00 am to 4:00 pm, reducing 14.3% track inspection workload from the current practice. The price of workload reduction is only a 2% chance of missed detection of slab deformation. The finding of this research can be used to enhance LCPST monitoring efficiency and reduce interruption to HSR operation, which is an essential step in promoting reliable and cost-effective track service.

Study on Spatial Mechanical Characteristic of High-Speed Railway Ballastless Slab Track on Subgrade

2012 ◽  
Vol 503-504 ◽  
pp. 1010-1015 ◽  
Author(s):  
Qing Yuan Xu ◽  
Bin Li
Keyword(s):  
Temperature Gradient ◽  
Mechanical Characteristic ◽  
High Speed ◽  
Three Dimensional ◽  
Calculation Model ◽  
Slab Track ◽  
Combined Load ◽  
Railway Line ◽  
Spring Element ◽  
Ballastless Track

By using beam element to model rail, spring element to model fastener, solid element to model different components of ballastless track, contact element to model the connection between each component of ballastless track, a statics three-dimensional nonlinear finite element mechanical model for calculating the forces transmission among rail, fastening and different component of ballastless slab track on subgrade was established. Experimental data of Suining-Chongqing railway line was given to validate the calculation model. Force of ballastless slab track on subgrade under gravity load, train load, uneven settlement load, temperature gradient load as well as combined load was analyzed. Results show that: spatial forces characteristic of ballastless slab track is very notable under train load; uneven settlement load as well as temperature gradient load has significant influence on the mechanical characteristic of ballastless slab track; force of ballastless slab track increases significantly under combined load than that of under any single load.

scholarly journals Vertical Dynamic Analysis of Ballastless Tracks on Train-Track- Bridge System

2020 ◽  
Vol 306 ◽  
pp. 02003
Author(s):  
Haoran Xie ◽  
Bin Yan ◽  
Jie Huang
Keyword(s):  
Track Structure ◽  
Vertical Acceleration ◽  
Train Track ◽  
Steel Spring ◽  
Slab Track ◽  
Ballastless Track ◽  
Track System ◽  
Train Speed ◽  
Track Bridge ◽  
Bridge System

In order to investigate the vertical dynamic response characteristics of train-track-bridge system on CWR (Continunously Welded Rail) under dynamic load of train on HSR (High-Speed Railway) bridge. Based on the principle of vehicle train-track-bridge coupling dynamics, taking the 32m simply supported bridge of a section of Zhengzhou-Xuzhou Passenger Dedicated Line as an example, the finite element software ANSYS and the dynamic analysis software SIMPACK are used for co-simulation, and bridge model of the steel spring floating slab track and the CRTSIII ballastless track (China Railway Track System) considering the shock absorbing steel spring, the limit barricade and the contact characteristics of track structure layers are established. On this basis, in order to study the dynamic response laws of the design of ballastless track structure parameters to the system when the train crosses the bridge and provide the basis for the design and construction, by studying the influence of the speed of train on the bridge, the damage of fasteners and the parameters of track structure on the train-track-bridge system, the displacement of rail, vertical vibration acceleration and wheel-rail force response performance are analyzed. Studies have shown that: At the train speed of 40 km/h, the displacement and acceleration of the rail and track slab in the CRTSIII ballastless track are smaller than the floating slab track structure, but the floating slab track structure has better vibration reduction performance for bridges. The acceleration of rail, track slab and bridge increases obviously with the increase of train speed, the rail structure has the largest increasement. Reducing the stiffness of fasteners could decrease the vertical acceleration response of the steel spring floating slab track system, the ability to absorb shock can be enhanceed by reducing the stiffness of the fastener appropriately. Increasing the density of the floating slab can increase the vertical acceleration of the floating slab and the bridge, thereby decreasing the vibration amplitude of the system.

Study on Precast Slab Track for Taiwan High Speed Rail

2012 ◽  
Vol 214 ◽  
pp. 276-281 ◽  
Author(s):  
Yan Chyuan Shiau ◽  
Ron Chen ◽  
Ming Hsi Lin ◽  
Chih Ming Huang
Keyword(s):  
Quality Management ◽  
Inventory Management ◽  
High Speed ◽  
Process Management ◽  
Key Factors ◽  
Material Management ◽  
High Speed Rail ◽  
Slab Track ◽  
Comprehensive Plan

High Speed Rail significantly saves transportation time between cities in which a stable slab track is an essential and important component. This article introduces the quality management on production of precast tracks system, which can act as a reference and application for the concrete industry in Taiwan. Case study is used to investigate the major content of this project which includes quality management, organizational structure, material management, process management and inventory management. Some other key factors are discussed which assure the success of Taiwan High Speed Rail project such as comprehensive plan in advance, strictly execution according to written document, and looking at the bigger picture & performing from the details and putting training into practice.

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