Evaluation of a Permit Vehicle Model Using Weigh-in-Motion Truck Records

Abstract

Permit truck models are used to consider local truck traffic in addition to national live load models in bridge design and rating practices. Weigh-in-motion (WIM) systems installed in the United States provide millions of truck records that can be used for evaluating such truck models. In this study, the standard permit vehicle in Wisconsin was evaluated by using six million WIM truck records collected in 2007. The evaluation was on the basis of statistical analyses of the maximum moments and shear in simply supported, 2-span, and 3-span continuous girders in the selected heaviest 5% of trucks in each vehicle class/group. The comparisons showed that 5-axle, short, single-unit trucks may cause larger moment/shear in bridge girders than the standard permit vehicle, and a 5-axle truck model was proposed to supplement the standard permit vehicle for possible use in bridge design and rating in Wisconsin.