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Showing 1 to 16 of 16 for “"Concrete crossties"”.
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Quantification of rail seat load distributions on concrete crossties
… magnitude and distribution of load imparted to concrete crosstie rail seats. The rail seat load distribution is critical to the analysis of failure mechanisms associated with rail seat deterioration (RSD), the degradation of the concrete surface at the crosstie rail seat. RSD can lead to wide …
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Freeze-thaw environment of precast concrete crossties and effect of vibration on fresh materials
High performance concrete is typically designed to achieve high strength and low permeability. These suppositions lead practitioners to install high performance concrete in outdoor environments assured that members will remain durable over scores of years. One such outdoor environment is in …
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Analysis of the performance and failure of railroad concrete crossties with various track support conditions
In North America, the use of concrete crossties has increased steadily over the past decade as they have emerged as an economic alternative to timber crossties to accommodate heavy axle freight train loads. As the number of concrete crossties has grown, the importance of understanding the …
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Flexural behavior of prestressed concrete monoblock crossties
As the use of concrete crossties increases for heavy-haul freight railroad lines in North America, it is becoming more critical to improve the understanding of their flexural behavior. This improved understanding can help to optimize current design and maintenance practices for concrete crossties, …
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Quantification of prestressed concrete railway crosstie flexural response: Implications for mechanistic design
Concrete is the dominant crosstie material choice for demanding locations on heavy axle load (HAL) freight railroads with steep grades, sharp curves, and high annual gross tonnage. Concrete crossties are also used in rail transit applications where safety and reliability of infrastructure is at a …
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Field test program of the concrete crosstie and fastening system
… rail program, the design and performance of concrete crossties and elastic fastening systems must be upgraded. As a part of a study aimed at improving concrete crossties and fastening systems, field experimentation was performed at the Transportation Technology Center (TTC) in Pueblo, CO by …
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Analysis of the design of railroad track superstructure components for rail transit applications
… of the performance of prestressed monoblock concrete crossties and premium elastic fastening systems, this project aimed to quantify the behavior of the aforementioned track superstructure elements under different rail transit loading conditions. Instrumentation was deployed at three …
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Flexural distress and degradation mechanisms in pretensioned concrete beams and railroad crossties
Crossties (sleepers) are an essential component of ballasted railroad track and concrete is a commonly used material for crossties in demanding locations such as heavy axle load (HAL) freight railroads, high-speed rail lines, and rail transit systems. Concrete crossties are often designed as …
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Polypropylene fiber reinforced concrete in railway crossties
Cracking of concrete crossties is a performance problem that reduces service life and increases maintenance costs. While strong in compression, plain concrete is relatively weak and brittle under tensile stresses. Inclusion of synthetic polypropylene macro fibers in concrete is known to improve …
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Determination of load path through concrete crosstie and fastening system: a laboratory and field investigation
… of the load path from rail-wheel to precast concrete crossties. In this research, the behavior of crosstie and fastening system is investigated through material-level, component-level and system-level laboratory and field experiments. The system-level experiments use three primary test …
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Increasing residual structural capacity of cracked concrete railroad crossties with polypropylene fibers
… research was to employ polypropylene fibers into concrete railroad crossties to increase its residual structural capacity once the concrete has cracked. The center negative flexural cracking is considered as a serious failure mode in concrete railroad crossties, which decreases structural capacity …
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Developing a prism qualification test to ensure adequate splitting resistance in pretensioned concrete railroad ties
… adequate splitting resistance in pre-tensioned concrete railroad ties. The research evaluated the influence of the edge distance, compressive strength of concrete and the type of wire indentation on bond performance between prestressing steel and concrete when using different concrete mixtures. …
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Analyses and modeling of track transition site responses from instrumented bridge approaches
… The amount of this gap observed underneath the concrete crossties contributed significantly to excessive transient responses commonly collected at the bridge approach locations. A numerical study was conducted using a state-of-the-art ballast particle image-aided discrete element method (DEM) to …
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Prestressed concrete railway crosstie support variability and its effect on flexural demand
… example, the current structural models used for concrete crosstie flexural analysis and design assume that the ballast bearing support is static and consistently located in a specific region under the crosstie. This assumption implies a linear behavior of the wheel-load bending moment …
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Abrasion resistance of concrete and the use of high performance concrete for concrete railway crossties
… project focused on the abrasion resistance of concrete railway crossties. In the first phase of this project, a series of high performance concrete mixes was developed that utilized different replacement levels of portland cement by silica fume (3%, 7% and 15%), class F fly ash (18%) and slag …
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Understanding the vertical load path under static and dynamic loads in concrete crosstie and fastening systems
… developing a mechanistic design approach for the crossties and fastening systems. It is important to follow the flow of forces through the system to understand the demands on each individual component. In spite of extensive research focusing on the vertical load path a lack of clear understanding …