Effects of spatial repeatability on long-term flexible pavement performance

The effects of spatial repeatability of dynamic tyre forces on the long-term performance of three typical British pavement constructions are investigated. Long-term pavement performance is calculated using a 'whole-life pavement performance Moder (WLPPM). The WLPPM is capable of predicting deterministic pavement damage due to realistic traffic and environmental loading, throughout the life of the pavement. Particular attention is given to modelling dynamic tyre forces and patterns of loading applied to the pavement by a typical fleet of heavy vehicles. A method is described for simulating vehicle fleets with varying degrees of spatial repeatability using a small number of dynamic tyre force histories. Results indicate that thinner pavements are most sensitive to the level of spatial repeatability exhibited by the vehicle fleet. Pavement damage predictions made without assuming an appropriate level of spatial repeatability can be in error by 20-150 per cent, the higher values being for thinner pavements that fail by fatigue damage.