Structural behaviours of railway prestressed concrete sleepers (crossties) with hole and web openings

As the crosstie beam in railway track systems, the prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed concrete has played a significant role as to maintain the high endurance of the sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed concrete sleepers in railway tracks, there have always been considerable demands from rail and track engineers to improve serviceability and functionality of concrete sleepers. For example, signaling, fibre optic, equipment cables are often damaged either by acute ballast corners or by tamping machine operation. There has been a significant need to re-design concrete sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study is the world first to experimentally investigate the effects of holes and web openings on structural behaviours of concrete sleepers under rail loading condition. The modified compression field theory for ultimate strength behaviours of concrete sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed concrete sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.