Spatial Repeatability of Dynamic Tyre Forces Generated by Heavy Vehicles

Abstract

Road damage due to heavy vehicles is thought to be dependent on the extent to which lorries in normal tra& apply peak forces to the same locations along the road. A validated vehicle simulation is used to simulate 37 leaf-sprung articulated vehicles with parametric variations typical of vehicles in one weight class in the highway vehiclefleet. The spatial distribution of tyre forces generated by each vehicle is compared with the distribution generated by a reference vehicle, and the conditions are established for which repeated heavy loading occurs at specific points along the road. It is estimated that approximately two-thirds of vehicles in this class (a large proportion of all heavy vehicles) may contribute to a repeated pattern of road loading. It is concluded that dynamic tyre forces are a signi9cant factor influencins road damage, compared to other factors such as tyre conzguration and axle spacing.In the United Kingdom in 1986,85590 per cent of trailers were fitted with leaf springs (11). In 1987, Morris (12) estimated that of new vehicles in the United States, up to 70 per cent of tractors and over 80 per cent of trailers had leaf spring suspensions. Morris also quoted the results of surveys in Canada (13) and Australia (14) which showed that leaf spring suspensions are the most popular on sani-trailers.

Dynamic Axle Force and Road Profile Identification Using a Moving Vehicle

“…Nevertheless, the larger amplitude components of the true forces are predicted very well. These peaks are an important factor in relation to pavement and bridge damage as they can indicate specific locations in pavements where damage will be concentrated (Cole and Cebon 1992). Table 1 presents the Root Mean Square Error (RMSE) of the identified forces expressed as a percentage of the maximum absolute true force magnitude.…”

“…It has been found that dynamic vehicle axle forces can increase the average road surface damage by up to four times compared to that caused by static axle forces alone (Cole and Cebon, 1992). Therefore, the minimisation of dynamic axle forces is important in order to promote long pavement life spans and ensure that bridge loads are small.…”

Truck fleet model for design and assessment of flexible pavements

“…and s y (w i ) is the Power Spectral Density (PSD) roughness in terms of wave number, i, which represents the spatial frequency [24]: (8) where w 0 is the discontinuity wave number and n 1 and n 2 define the slopes. According to [30] the discontinuity between two branches of the PSD happens at a wavelength of approximately 6.3m, which is 1/2π cycles/metre taken as the datum value for s y (w 0 ).…”

“…Cole and Cebon [8] also tried to reproduce patterns of spatial repeatability but did not allow for the variability in the vehicle dynamic properties. This paper describes a computer model which predicts the dynamic behaviour of a truck fleet.…”

The use of Bayesian statistics to predict patterns of spatial repeatability

“…Cole & Cebon [4] performed a numerical investigation of spatial repeatability using an experimentally validated two-dimensional articulated vehicle model. They generated a fleet of thirty-seven leaf sprung vehicle models with similar geometry and eight varying parameters relating to the ride characteristics, identifying repeatable patterns of dynamic tyre forces.…”