Live Load Models Based on WIM Data

The objective of the paper is to present the results of weigh-in-motion (WIM) measurements carried out in Michigan. Selected bridges were instrumented and truck weights and axle configurations were determined from strains in lower flanges of girders. Normal traffic flow was considered. The trucks were run through influence lines to determine the maximum moments and shears for various bridge span lengths. The resulting moments and shears are plotted on the normal probability paper to facilitate statistical interpretations. The obtained load distributions are compared with the results of truck surveys carried out using the stationary scales at truck weigh station. The study indicates that overloaded trucks avoid going through the scales and the weigh station data is biased to less heavy vehicles.