Flexural Performance Evaluation of Different Countries Concrete Sleepers for The Case Of Ethiopian Railway Track Design
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Date
2015-07
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Addis Ababa University
Abstract
Prestressed concrete sleepers are the most widely used sleeper type in various countries for
railway track system. This thesis evaluates the flexural performance of Australian German,
British and Chinese prestressed concrete sleepers in comparison with the currently used
sleeper in Ethiopia. The state of art of literature review has been discussed in order to assess
the experiences of these countries in railway prestressed concrete sleeper. Codes of
standards for prestressed sleeper recommended different types of concrete sleepers
according to track gauge and axle load capacity. Sleepers are subjected to different types of
load such as quasistatic, dynamic load and combined quasistatic and dynamic loading. In
some codes like British and German accidental, exceptional and services load are included in
the design.
Finite element (FE) modeling and analysis is performed using FE software packages ANSYS.
The design rail seat load is calculated according to the code provisions of respective
countries code of standard. For comparison of the results of rail seat and sleepers center
positive and negative loadings, AREMA standard is used as a reference. The result obtained
from both rail seat positive and negative loads shows a good result which is below AREMA
recommendations. For results obtained from sleeper center loading there was a variation of
about average of 20%. The second FE analysis has been conducted according to actual
ballast pressure distribution under sleepers provided by each country code and Chinese
code. From the analysis result it has been observed that, the Australian and German concrete
sleeper shows a good response at rail seat and sleeper center respectively. The German
concrete sleeper relatively shows a better result when compared to British concrete sleeper
under both rail seat and sleeper center. Finally, dynamic analysis has been made to see how
these loads affect the flexural performance of concrete sleepers. The result showed that the
Australian and china concrete sleepers observed a large amount of deflection when
compared to other. In contrast the German concrete sleeper showed a small deflection.
Based on the analysis result the German concrete sleeper was selected in terms of its general
flexural performance. Lastly, the recommended sleeper cross-section shows a reduced stress
when compared with others concrete sleepers.
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Keywords
Prestressed concrete sleepers, Flexural performance, Rail seat bending moment, Sleeper center bending moment, Dynamic analysis