IMPACT ASSESSMENT IN THE PAVEMENT LIFE CYCLE DUE TO THE OVERWEIGHT IN THE AXLE LOAD OF COMMERCIAL VEHICLES

Commercial vehicles may have different wheel and axle set ups, usually presenting single or dual wheels, and single-axle or dual or triple tandem-axles. In pavement design, requests caused by these various set ups of wheels and axles are converted into the request of the standard axle, loading 8.17 ton-force, which together make up the Number "N". Due to mechanical manufacture of axles and wheels, and to ensure that the pavements will not receive excessive point loads that might lead to its rupture, there are set weight limits for axle set ups. In Brazil, the legislation on dimensions and weights of vehicles is Resolution no. 12, dated February 6, 1998, CONTRAN - National Traffic Council. Despite being established by laws, not all roads are properly invigilated to assure these limits are being respected, such as free access roads, roads with insufficient weighing scales for proper control or urban roads. Although overweight axles may cause damage to vehicles, as well as high operation and maintenance costs, depending on the profile of the conductors, it may be more common to disrespect these limits, which shortens the life cycle of pavements. This article aims to analyse and compare the effect on the life cycle of the pavement when requested by single axle with single wheels, and single-axles, dual and triple tandem-axles with dual wheels, when the axles have 20%, 35%, 50% and 70% overload Brazilian legal values, according to the equivalences axles for AASHTO and USACE methods.