Accordingly, there is a need to develop a new
design concept for concrete sleepers in which it
permits controllable cracks to occur so that the true
capacity of the sleepers could be exploited. To
develop the limit states design approach, studies of
the response of concrete sleepers to high-magnitude
short-duration loading were carried out at: UBC
Canada [7]; RTRI Japan [8]; CHARMEC Sweden [9];
and recently UOW Australia [1]. In general, the
current design methods are very conservative.
However, there is often a special case that a rail
organization could take risk of high maintenance cost
by introducing its own fit-for-purpose dynamic
impact factor but still exercising the existing design
concept. It is important to note that this practice is
not commonly standardized and has not been
adequately calibrated to ensure structural safety.
Although there has been an attempt to develop a
low-profile concrete sleeper for a specific use as
timber-replacement sleepers, the in-field
performance of such product is very poor and its
design method could be doubtful [10].