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Dynamic crack propagations in prestressed concrete sleepers in railway track systems subjected to severe impact loads / Sakdirat Kaewunruen in Journal of structural engineering, Vol. 136 N° 6 (Juin 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 749-754 Titre : Dynamic crack propagations in prestressed concrete sleepers in railway track systems subjected to severe impact loads Type de document : texte imprimé Auteurs : Sakdirat Kaewunruen, Auteur ; Alex M. Remennikov, Auteur Année de publication : 2011 Article en page(s) : pp. 749-754 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Prestressed  concrete  sleeper  Repeated  impact  behavior  Severe  impact  Crack  propagation  Ballasted  railway  track Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Prestressed concrete sleepers (or railroad ties) are the crosstie beam support in railway track systems. They are designed and constructed under flexural constraints in order to carry and transfer the dynamic wheel loads from the rails to the ground. Under perfect wheel and rail conditions, the dynamic loading on railway tracks could be treated as a quasi-static load using a dynamic impact factor. The current design method for the prestressed concrete sleepers taking into account the quasi-static effect is based on allowable stress where crack initiation is not permitted. In reality, the impact events are often detected due to the uncertainties of wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration. Over the design life span of the prestressed concrete sleepers, there exists the feasibility of extreme and repeated impact loading events. These have led to two proposed limit states for the consideration of structural engineers: ultimate limit states and fatigue limit states. Prestressing techniques have been long used to maintain the high endurance of the sleepers under repeated impact cycles. In spite of the most common use of the prestressed concrete sleepers, their impact behavior and capacity under the repetitions of severe impact loads are unclear. This paper presents the experimental investigation aimed at understanding the dynamic crack propagations in prestressed concrete sleepers in railway track structures under repeated impact loading. The impact forces have been correlated against the probabilistic track force distribution obtained from an Australian heavy haul rail network. The effects of track environment including soft and hard tracks are highlighted in this paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i6/p749_s1?isAuthorized=no [article] Dynamic crack propagations in prestressed concrete sleepers in railway track systems subjected to severe impact loads [texte imprimé] / Sakdirat Kaewunruen, Auteur ; Alex M. Remennikov, Auteur . - 2011 . - pp. 749-754. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 749-754 Mots-clés : Prestressed  concrete  sleeper  Repeated  impact  behavior  Severe  impact  Crack  propagation  Ballasted  railway  track Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Prestressed concrete sleepers (or railroad ties) are the crosstie beam support in railway track systems. They are designed and constructed under flexural constraints in order to carry and transfer the dynamic wheel loads from the rails to the ground. Under perfect wheel and rail conditions, the dynamic loading on railway tracks could be treated as a quasi-static load using a dynamic impact factor. The current design method for the prestressed concrete sleepers taking into account the quasi-static effect is based on allowable stress where crack initiation is not permitted. In reality, the impact events are often detected due to the uncertainties of wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration. Over the design life span of the prestressed concrete sleepers, there exists the feasibility of extreme and repeated impact loading events. These have led to two proposed limit states for the consideration of structural engineers: ultimate limit states and fatigue limit states. Prestressing techniques have been long used to maintain the high endurance of the sleepers under repeated impact cycles. In spite of the most common use of the prestressed concrete sleepers, their impact behavior and capacity under the repetitions of severe impact loads are unclear. This paper presents the experimental investigation aimed at understanding the dynamic crack propagations in prestressed concrete sleepers in railway track structures under repeated impact loading. The impact forces have been correlated against the probabilistic track force distribution obtained from an Australian heavy haul rail network. The effects of track environment including soft and hard tracks are highlighted in this paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i6/p749_s1?isAuthorized=no