Measurement of central or offset axle load by axle-mounted strain gauges

摘要

It is an accepted fact that the overloading of road freight vehicles causes not only mechanical failures on the vehicles themselves, but also greatly accelerates deterioration of road surfaces [1]. A power law curve for equivalent road damage is accepted in the literature, with an exponent of 4 or more, making an axle carrying a 11-tonne weight roughly 46% more damaging than one carrying 10 tonnes [2]. For this reason, national legislation throughout the world stipulates limits to the loading of axles and gross vehicle weights, and public bodies attempt to enforce these limits through roadside weighing and inspection of vehicles. The problem of overloading is acute in Africa, where freight routes are long, standards of pavement construction variable, incentives to overload high and enforcement poor. One comprehensive survey [1] has reported that 20% of 53 969 axles weighed were in excess of the legal limit of 8.2 tonnes, and found one route on which the proportion stood at 30%, and those above 10 tonnes were 20%.