Road authorities in resource based economies are frequently challenged by the demands of heavy equipment operators requiring access to remote sites. The access to these sites is often along low volume, structurally under-designed pavements and consequently many of these pavements suffer premature deterioration as a result of vehicle overloads. To overcome this, agencies impose restrictions that are based upon Load Equivalency Factors (LEF) which were initially developed at the AASHTO test road and have become the basis not only for overload permitting but also for pavement design. A recent round-table discussion at the Pavements Standing Committee (PSC) of the Transportation Association of Canada, in April 2005, highlighted the wide range of approaches to overload permitting across Canada. This paper first summarizes the various approaches to overload permits in Canadian provinces and then describes a test conducted at the Nisku Test Road in Alberta. The Nisku Test road is comprised of two thin membrane pavement sections that have been constructed and instrumented with the specific aim of monitoring real-time pavement response under vehicular loads. Within the Nisku Business Park, the Province of Alberta has allowed a 25% overload on tandem 17,000kg axles and this paper describes the finding of a series of tests conducted in 2005.
Menu
