Experimental investigation into the lateral resistance of Y-shape steel sleepers on ballasted tracks

2020 ◽  
pp. 095440972097259
Author(s):  
Jabbar Ali Zakeri ◽  
Yaser Bahari ◽  
Kaveh Yousefian
Keyword(s):  
Significant Contribution ◽  
Railway Track ◽  
Structural Behavior ◽  
Resistance Force ◽  
Loading Test ◽  
Conventional Concrete ◽  
Loading Direction ◽  
Lateral Resistance ◽  
Different Types ◽  
Longitudinal Resistance

Track lateral resistance ensures the track stability under operation and during its service life in lateral and longitudinal directions. Numerous methods and techniques have been considered to enhance track lateral resistance. Since sleeper, as one of the railway track superstructure components, has a significant contribution in providing the lateral resistance, using different types of sleepers, like Y-shape one, would alter the track lateral resistance. The utilization of Y-shape steel sleepers in railway tracks needs further investigation to comprehend the structural behavior. Hence, in this paper, the lateral resistance of the Y-shape steel sleeper was experimentally investigated by performing the lateral track panel loading test (LTPT) and single tie push test (STPT). The longitudinal resistance force (LRF) in STPT depends on the loading direction. The LRF was specified as 16 kN in Y-top direction and 13 kN in Y-bottom direction for a single sleeper. The LRF in STPT was enhanced by 90% on average compared to the conventional concrete sleeper. The LRF in LTPT was also obtained as 18 kN, and its increasing percentage was measured as 12.5%.

Experimental investigation into the longitudinal resistance of ballasted railway track

2020 ◽  
pp. 095440972097552
Author(s):  
Jabbar Ali Zakeri ◽  
Kaveh Yousefian
Keyword(s):  
Experimental Investigation ◽  
Measurement Technique ◽  
Test Method ◽  
Railway Track ◽  
Resistance Force ◽  
Test Conditions ◽  
Longitudinal Stiffness ◽  
Longitudinal Resistance ◽  
Two Parameters ◽  
Force Displacement

In this paper, a new test method and a measurement technique were proposed to evaluate the track longitudinal resistance (TLR). The three-stage track longitudinal behavior was assessed. The track longitudinal stiffness (TLS) and track longitudinal resistance force (TLRF) were defined based on the analyses of force-displacement curves in each test. Next, the effect of ballast geometry on these two parameters was scrutinized. The resisting mechanism was described. Finally, the share of ballast geometry components in providing the TLS was determined, and contribution percentages were verified by comparing the results with those of previous studies. Nine test conditions were considered. The ballast depth (BD) was set at 30 cm, 40 cm, and 50 cm. In each ballast depth, the TLR was evaluated with and without the crib and shoulder ballasts. The average values of TLS and TLRF were obtained as 22.94 kN/mm and 35.52 kN, and the total share of the base, crib, and shoulder ballast was calculated as 21%, 67%, and 12%, respectively. It was found that the crib ballast had the most impact on the TLS and enhanced the TLS and TLRF up to 4.11 and 3.25 times.

Effect of different contact surfaces between concrete sleeper and ballast on mobilized lateral resistance against impact loads

2016 ◽  
Vol 231 (6) ◽  
pp. 678-689 ◽  
Author(s):  
Ahmad Hosseini ◽  
Morteza Esmaeili
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Static Friction ◽  
Railway Track ◽  
Rolling Stock ◽  
Lateral Impact ◽  
Loading Test ◽  
Analysis And Design ◽  
Dynamic Friction Coefficient ◽  
Lateral Resistance

The amount of ballast particles surrounding a railway track significantly influences its resistance in all directions. As time goes by, with the development of high-speed trains, more attention has been paid to this issue owing to the increase in dynamic effects of rolling stock on track loading. The focus of the present study is on the investigation of the interaction between different surfaces (base, crib, and shoulder) of concrete sleeper and their adjacent ballast layer along with the related parameters under lateral impact loading condition. In this regard, by utilizing a pendulum loading test device, a number of lateral impact tests were conducted on an instrumented concrete sleeper in laboratory. On the basis of experimental results, the average contribution of base, crib, and shoulder zones in the total dynamic lateral resistance of sleeper was calculated as 48%, 23%, and 29%, respectively. Furthermore, in the lateral impact force domain of 13–28 kN, the sleeper–ballast dynamic friction coefficient at base and crib zones varied in the ranges 0.8–1.5 and 0.5–0.6. Moreover, a maximum impact factor of 2.5 was obtained for analysis and design purposes. It should be stated that the trend of laboratory results confirmed the common static friction coefficient of 0.8.

scholarly journals Behavior of Quarry Rock Dust, Fly Ash and Slag Based Geopolymer Concrete Columns Reinforced with Steel Fibers under Eccentric Loading

2021 ◽  
Vol 11 (15) ◽  
pp. 6740
Author(s):  
Rana Muhammad Waqas ◽  
Faheem Butt
Keyword(s):  
Fly Ash ◽  
Concrete Cover ◽  
Steel Fibers ◽  
Structural Behavior ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
Source Materials ◽  
Rock Dust

Geopolymer concrete, also known as an earth-friendly concrete, has been under continuous study due to its environmental benefits and a sustainable alternative to conventional concrete construction. The supplies of many source materials, such as fly ash (FA) or slag (SG), to produce geopolymer concrete (GPC) may be limited; however, quarry rock dust (QRD) wastes (limestone, dolomite, or silica powders) formed by crushing rocks appear virtually endless. Although significant experimental research has been carried out on GPC, with a major focus on the mix design development, rheological, durability, and mechanical properties of the GPC mixes; still the information available on the structural behavior of GPC is rather limited. This has implications in extending GPC application from a laboratory-based technology to an at-site product. This study investigates the structural behavior of quarry-rock-dust-incorporated fiber-reinforced GPC columns under concentric and eccentric loading. In this study, a total of 20 columns with 200 mm square cross-section and 1000 mm height were tested. The FA and SG were used as source materials to produce GPC mixtures. The QRD was incorporated as a partial replacement (20%) of SG. The conventional concrete (CC) columns were prepared as the reference specimens. The effect of incorporating quarry rock dust as a replacement of SG, steel fibers, and loading conditions (concentric and eccentric loading) on the structural behavior of GPC columns were studied. The test results revealed that quarry rock dust is an adequate material that can be used as a source material in GPC to manufacture structural concrete members with satisfactory performance. The general performance of the GPC columns incorporating QRD (20%) is observed to be similar to that of GPC columns (without QRD) and CC columns. The addition of steel fibers considerably improves the loading capacity, ductility, and axial load–displacement behavior of the tested columns. The load capacities of fiber-reinforced GPC columns were about 5–7% greater in comparison to the CC columns. The spalling of concrete cover at failure was detected in all plain GPC columns, whereas the failure mode of all fiber-reinforced GPC columns is characterized with surface cracking leading to disintegration of concrete cover.

scholarly journals Comparative Study of High-Performance Concrete Characteristics and Loading Test of Pretensioned Experimental Beams

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 427
Author(s):  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Load Capacity ◽  
Materials Testing ◽  
Loading Test ◽  
Conventional Concrete ◽  
Concrete Mechanical Properties ◽  
Normal Strength

High-performance concrete (HPC) is subjected to wide attention in current research. Many research tasks are focused on laboratory testing of concrete mechanical properties with specific raw materials, where a mixture is prepared in a relatively small amount in ideal conditions. The wider utilization of HPC is connected, among other things, with its utilization in the construction industry. The paper presents two variants of HPC which were developed by modification of ordinary concrete used by a precast company for pretensioned bridge beams. The presented variants were produced in industrial conditions using common raw materials. Testing and comparison of basic mechanical properties are complemented with specialized tests of the resistance to chloride penetration. Tentative expenses for normal strength concrete (NSC) and HPC are compared. The research program was accomplished with a loading test of model experimental pretensioned beams with a length of 7 m made of ordinarily used concrete and one variant of HPC. The aim of the loading test was to determine the load–deformation diagrams and verify the design code load capacity calculation method. Overall, the article summarizes the possible benefits of using HPC compared to conventional concrete.

Structural Systems for Mass Timber Buildings

2019 ◽  
Author(s):  
Tim Gleason ◽  
Gordana Herning ◽  
John Klein
Keyword(s):  
Affordable Housing ◽  
Lateral Force ◽  
Timber Structures ◽  
Braced Frames ◽  
Conventional Concrete ◽  
Composite Systems ◽  
Lateral Resistance ◽  
Mass Timber ◽  
Story Building ◽  
Gravity System

<p>This paper investigates the design of lateral force resisting systems (LFRS) for multi-story mass timber structures in Boston, MA. Structural and environmental tradeoffs of replacing conventional concrete cores or steel braced frames with glue-laminated timber (GLT) braced frames are evaluated through numerical analyses of 8-, 12-, and 18-story building prototypes. Finding an optimal timber gravity system configuration is followed by examining lateral resistance of the prototypes. The resulting designs demonstrate a practical approach to assist designers in selecting a lateral system during the early stages of conceptual design. This research was conducted in parallel with a related study for implementation of mass timber in affordable housing in Boston, enabling a comparison between composite systems and all-timber structures.</p>

scholarly journals Ballast bed resistance characteristics based on discrete-element modeling

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878146 ◽  
Author(s):  
Zhiping Zeng ◽  
Shanyi Song ◽  
Weidong Wang ◽  
Haijian Yan ◽  
Guoshu Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Discrete Element ◽  
Discrete Element Modeling ◽  
Slope Gradient ◽  
Three Dimensional Model ◽  
Lateral Resistance ◽  
In Situ Experiments ◽  
Distribution Limits ◽  
Longitudinal Resistance

In this study, in situ experiments were conducted to study the changing characteristics of the lateral and longitudinal resistance of a ballast bed, and a three-dimensional model for the ballast bed and sleeper was constructed based on the discrete-element method. The effects of the lateral and longitudinal resistance of the ballast bed, such as gravel ballast grading, sleeper depth, the angle of the shoulder slope, and ballast bed shoulder width, among others, were studied. The results suggest that (1) the lateral and longitudinal resistance of the ballast bed increases with the widening of ballast grading, and within the size distribution limits, the resistance of the ballast bed satisfies the specification; (2) the lateral and longitudinal resistance of ballast bed increases with an increase in the sleeper depth and the resistance of ballast bed satisfies the specifications for sleeper depth greater than 150 mm; (3) the lateral resistance of the ballast bed increases with a decrease in the angle of the shoulder slope, whereas the longitudinal resistance remains unchanged and the resistance of the ballast bed satisfies the specifications for slope gradient of 1:1.75 or less; and finally, (4) the lateral resistance of the ballast bed increases with the widening of the ballast bed shoulder, whereas the longitudinal resistance remains unchanged, and the resistance of ballast bed satisfies the specifications when the shoulder width is greater than 400 mm.

scholarly journals Longitudinal displacements of railway jointless track due to local temperature difference on its length

2020 ◽  
Vol 2020 (2) ◽  
pp. 11-27
Author(s):  
Włodzimierz Bednarek
Keyword(s):  
Temperature Difference ◽  
Cross Sections ◽  
Analytical Form ◽  
Railway Track ◽  
Local Temperature ◽  
Track Length ◽  
Segment Length ◽  
Longitudinal Resistance ◽  
Value Changes ◽  
Acting Force

In the paper is shown an analysis of a CWR track’s longitudinal displacements due to a local temperature difference on its length. The thermical forces on the railway track length arise due to a local temperature difference of rail, causing the local, zonal the longitudinal displacements of rail cross-sections. Axial displacements of track induce in succession a longitudinal reaction of roadbed in such a degree on which a arising displacements allow. Additionally a arising during track operating a variable longitudinal resistance on track’s length (generated among other things by different state of ballast compaction, different pressure force of rail foot to divider), periodical acting force from vehicles, different value of adhesion wheels with rails and also different stage of rail heating, cause a disturbance section of equilibrium state of CWR track. In certain cases it assumes a shape of rails micro displacements, which can take a form e.g. creep displacements leading to value changes of longitudinal forces on this segment length with arising displacements. In paper analytical form of considered problem is given and computational examples, diagrams and tables reflecting influence of analyzed parameters on obtained a CWR track’s longitudinal displacements due to local temperature difference on its length is inserted Keywords: CWR track; Longitudinal displacement; Local temperature difference

United and Uniting Churches

2017 ◽  
Author(s):  
James Haire
Keyword(s):  
Nineteenth Century ◽  
Significant Contribution ◽  
New Delhi ◽  
World Council Of Churches ◽  
Ecumenical Movement ◽  
The Third ◽  
The World ◽  
Different Types ◽  
World Council ◽  
History Of

United and uniting churches have made a very significant contribution to the ecumenical movement. In seeking to assess that contribution, the chapter first defines what these churches are, considers the different types of union that have been created, examines the characteristics of these churches, and looks at the theological rationale for them. It goes on to trace the history of their formation from the beginning of the nineteenth century, and particularly during the years leading up to and following the Third Assembly of the World Council of Churches at New Delhi in 1961, under the influence of Lesslie Newbigin. Giving a theological assessment, it emphasizes that the existence of these churches, despite difficulties, provides places where the final unity of Christ’s one body is most clearly foreshadowed. They will always present proleptic visions of that goal.

scholarly journals Mineralogy and Geochemistry of Fluvial-Lacustrine Pisolith Micronodules from the Roztoka Odrzańska, Odra River, NW Poland

Geosciences ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Łukasz Maciąg ◽  
Urszula Rydzewska ◽  
Artur Skowronek ◽  
Sylwester Salwa
Keyword(s):  
Significant Contribution ◽  
Manganese Content ◽  
River Mouth ◽  
Geochemical Data ◽  
Iron Hydroxides ◽  
Szczecin Lagoon ◽  
Different Types ◽  
Odra River ◽  
Moderate Climate ◽  
Nw Poland

Small-sized ferruginous micronodules or pisolith nodules, frequently occurring in inland freshwater systems in moderate climate zones, are important indicators of groundwater level changes and early diagenetic processes, especially within the Pleistocene post-glacial sedimentary systems, including swamps, peatbogs, rivers, or lakes. Compared to the other geochemical environments, pisolith nodules are usually dominated by iron hydroxides and oxides. In most cases, described micronodules indicate high phosphatization, significant contribution of allogenic detrital components, and low manganese content. The major aim of the article is to present textural, geochemical, and mineralogical variability of pisolith nodules recovered from the Roztoka Odrzańska, Odra river mouth area, NW Poland. We describe genetical relations between different types of pisoliths and try to interpret the possible formation phenomena. Analyzed loose ferruginous micronodules were separated from the lacustrine silty-clayey sapropel muds and gyttja, later analyzed using optical microscopy, SEM-energy dispersive x-ray (EDX), and XRD methods. As a reference material, we use archival iron bog ores and geochemical data of different types of nodules. Additionally, we describe previously unknown siderite-rich nodules found in neighboring sites of the Dąbie Lake and the Szczecin Lagoon.

scholarly journals Response of tapered piles in cohesionless soil based on model tests

2010 ◽  
Vol 40 ◽  
pp. 85-92 ◽  
Author(s):  
Suman Manandhar ◽  
Noriyuki Yasufuku ◽  
Kiyoshi Omine ◽  
Taizo Kobayashi
Keyword(s):  
Skin Friction ◽  
Model Tests ◽  
High Density ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Loading Test ◽  
Tapered Pile ◽  
Different Types ◽  
Steel Piles ◽  
Settlement Ratio

This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.

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