Paulos, Tibebu (2016) Structural Response Evaluation of Concrete Sleeper under Increasing Train Speed and Axle Load. Masters thesis, Addis Ababa University.
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Abstract
Nowadays the railway tracks are subjected to high train speed and freight tonnage which in turn cause deterioration to track components and affect the geometry and service life of the track. The type of track loading and its quantity combined with varying traffic conditions have a great effect on the structural behaviour of sleepers. Hence the need for studying the sleepers’ structural response under different loading conditions such as increasing train speed and axle load is of great significance. To study the effects of increase in speed and axle load on the structural response of prestressed concrete sleeper, a three-dimensional ballast track and a separate concrete sleeper with a detailed feature are modelled by using commercial finite element package, ANSYS. Speed is considered at four different rates which are 80, 120, 160 and 200 km/h and axle load at 23, 25, 27 and 29 ton. Since it is practical to improve track property before increasing load above its design limit, the existing track model (Model 1) is modified to obtain a track model with better rail profile and pad stiffness (Model 2) and the effect of track improvement on structural response of the sleeper is investigated. Two types of ballast support conditions, which are mentioned in AREMA manual, are also considered to investigate the effect of difference in support condition. These support conditions are categorised as Case 1(Leff ≅ 2L/3) and Case 2 (Leff = L) for the purpose of this thesis. Both dynamic and static structural analyses are employed to get rail seat load from the track models and to analyse the response of prestressed concrete sleeper respectively. The analysis results show that the increase in speed from 80 to 200 km/h which is 150% increment increases the bending stress and deflection in about 40.3% and increase in axle load from 23 ton to 29 ton which is about 26.1% increment increases the bending stress and deflection in about 26.1% with Model 1. With the same increment in speed and axle load, improving the track model (Model 2) reduced the percentage increment of bending stress and deflection by about 13.8% in the case of speed and 12.6% in the case of axle load. This indicates the bending stress and deflection of the sleeper are affected slightly by the speed variation while axle load increment affects significantly.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Concrete Sleeper, Train Speed, Axle Load, Ballast Pressure |
| Subjects: | Q Science > Q Science (General) T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General) T Technology > TF Railroad engineering and operation |
| Divisions: | Africana |
| Depositing User: | Andriamparany Edilbert RANOARIVONY |
| Date Deposited: | 24 Oct 2018 08:46 |
| Last Modified: | 24 Oct 2018 08:46 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/7044 |
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