Localised bridge loading for south africa using wim data

Abstract

Bridges in South Africa are designed in accordance with TMH7, which was first published in 1981 and revised in 1989. Since the publication of the code, there have been revisions to traffic legislation and the nature of the vehicles that currently occupy our roads has changed over the past forty years with respect to gross vehicle weight, axle weight, number of axles, axle spacing and dynamic amplification. There is enough reason to believe that bridge loading may not be the same across our provinces as it is highly dependent on localised economic activity. This study investigates bridge loading across South Africa using weigh-in-motion data from six provinces. The number of vehicle records captured by WIM stations are approaching one hundred million and in-house software, together with extreme value statistics are used to compare load effects from the available data. The aim is to identify province specific bridge loading to prevent unnecessary conservatism in some locations.