Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
When designing roads it’s important to know
what loads will be
driven on it. The axles on heavy vehicles can either have super single tires or
dual tires which, according to studies, damage the roads differently. The Swedish
Transport Administration is developing an understanding for the character of
these different kinds of axle and tire types on the loads induced on Swedish
roads. In this thesis a field study was conducted to determine the distribution
between axles with super single tires and axles with dual tires on heavy vehicles.
A highway, a country road and a national road were investigated during the
study. The result showed that the number of trucks with single tire axles, i.e.
those with super single tires, varies between 39 and 48 percent on the different
types of road. That the truck has a single tire axle means that the truck has at
least one axle with single tires in addition to the steering axle. A small study was
conducted to determine the width of tires on heavy vehicles.
A comparison of trucks with single- and dual tire axles was carried out in
terms of degradation of the roads. Permanent deformation of unbound layers and
fatigue cracking were investigated since these degradation mechanisms are
currently used as design parameters in the design of roads. Load values from
Bridge Weight In Motion (BWIM) data were used in the calculations and vehicle
type 113, 123 and 12211 were investigated. Permanent deformation and fatigue
cracking were calculated according to the criteria given in ATB VÄG 2005.
Dissipated Creep Strain Energy (DCSE) has been calculated for the selected
truck types. The study showed that trucks with axles with single tires accelerate
the degradation of the roads. The permanent deformation was almost the same
for the two different kinds of axle types.
2011. , 66 p.
dual tires, super single tire, ATB VÄG 2005, DCSE, permanent deformation, fatigue cracking, BWIM.