Railway sleeper is a main part of railway track structures. Its role is to distribute loads from the rail foot to the underlying ballast bed. There is a widespread suspicion based on the industry experience that railway concrete sleepers have reserves of strength that are untapped. It is thus important to ascertain the spectrum and amplitudes of forces applied to the railway track, to understand more clearly the manner in which track components respond to those forces, and to clarify the processes whereby concrete sleepers in particular carry those actions. Cracks in concrete sleepers have been visually observed by many railway organizations. The principal cause of cracking is the infrequent but high-magnitude wheel loads produced by a small percentage of “bad” wheels or railhead surface defects. Those loads are of short duration but of very high magnitude. For instance, the typical loading duration produced by wheel flats is about 1-10 msec, while the force magnitude can be over 400 kN per rail seat. Current design philosophy for prestressed concrete sleepers is based on permissible stress principle, which are unrealistic to the actual dynamic loads on tracks. In order to devise a new limit states design concept, the research efforts are required to perform comprehensive studies of the loading conditions, the static behaviour, the dynamic response, and the impact resistance of the prestressed concrete sleepers. This paper presents the results of experimental and numerical studies aimed at predicting the dynamic responses of railway concrete sleepers. Experimental data also convey the exact failure modes for railway prestressed concrete sleepers under static and impact loadings. A high-capacity drop weight impact testing machine was constructed at the University of Wollongong to evaluate the ultimate capacity of prestressed concrete sleepers under impact loads. Energy absorption capacity of the prestressed concrete sleepers was also evaluated to determine the amount of energy required to fail the sleeper under impact load. Static and impact tests were carried out using the Australian-manufactured prestressed concrete sleepers.
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