Sleeper Spacing Optimization on Ballasted Track Structure
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Date
2020-08
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Addis Ababa University
Abstract
Now days’ transportation plays a great role for enhancing exchange or flow of row material, manpower, and information from place to place. Hence different means of transportations are emerged newly. For instance, railway is currently constructed with ballast or without ballast throughout the world to improve transportation of goods in general. However, railway structure needs huge investment designing it through optimum technique by improving serviceability and durability is a genuine question for professionals.
Ballasted track is the most commonly used railway structure in the world because of low construction cost and it has sufficient lateral load resistance capacity. For such tracks sleeper plays a great role in safely and smoothly transferring the axle load from the rail to the underneath ballast, sub ballast, and finally to the formation level. Beside to this sleeper affect the cost of construction, while providing sleepers at dense manner costs more even if safety is assured.
Currently, the provision of sleepers on ballasted track system is based on code recommendations which are different for different countries. This way of designing the track system greatly affect cost of construction even though strength criteria is attained. Therefore, providing sleepers in such away is expensive. So, numeric analysis on spacing of sleepers should be done using classic optimization techniques for newly constructed railways and to check the serviceability of constructed railroads.
Generally, this thesis deals about obtaining the optimum spacing of pre stressed concrete sleeper on the conventional track structure with various curvature values. The numeric analysis is done using the basic finite element methods and/or software i.e. ANSYS through considering train speed, axle load, and track curvature as design variables to obtain the optimum sleeper spacing.
Therefore, the finding of this research attempts to save extra cost through placing sleeper at optimum spacing obtained from analysis. For instance, sleepers provided at AALRT for tangent tracks with train speed less than 70 km/h is 600 mm but from analysis the spacing is 650 mm this leads to a conclusion of around 7.2 percentage of sleeper cost can be saved.
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Keywords
Ballasted Track, Pre Stressed Concrete Sleeper (PCS), Sleeper Spacing