Spatial repeatability arises because trucks are similar in weights, dimensions, and dynamic characteristics and travel at similar speeds. As a result, each vehicle will apply its peak forces at approximately the same places along the pavement surface (Cole, Cebon 1992).
Cole et al. defined the spatial repeatability index (SRI) as the correlation coefficient between a dynamic tyre force histories,
(1)
where x and y are dynamic tyre forces histories,
mx and my are the mean forces of x and y, respectively,
and σx and σy are the standard deviations of x and y, respectively (Cole, Cebon 1992; Cole et al. 1996).
An alternate measure of spatial repeatability, suggested by Cole, is the fleet normalised aggregate tyre force,
(2)
where
Fi,jk is the tyre force at the i-th road point due to the k-th axle of the j-th vehicle,
m is the number of axles on each vehicle,
NV is the total number of vehicles,
and
is the mean of the double sum in the numerator (Cole et al. 1996).
The fleet normalised aggregate force gives a spatial (time-domain) picture of the cumulative pattern of traffic loading.
Cole et al. defined the spatial repeatability index (SRI) as the correlation coefficient between a dynamic tyre force histories,
(1)where x and y are dynamic tyre forces histories,
mx and my are the mean forces of x and y, respectively,
and σx and σy are the standard deviations of x and y, respectively (Cole, Cebon 1992; Cole et al. 1996).
An alternate measure of spatial repeatability, suggested by Cole, is the fleet normalised aggregate tyre force,
(2)where
Fi,jk is the tyre force at the i-th road point due to the k-th axle of the j-th vehicle,
m is the number of axles on each vehicle,
NV is the total number of vehicles,
and
is the mean of the double sum in the numerator (Cole et al. 1996). The fleet normalised aggregate force gives a spatial (time-domain) picture of the cumulative pattern of traffic loading.
