Analysis of permit vehicle loads in Wisconsin

Abstract

This study evaluated the impact of the 250-kip Wisconsin Standard Permit Vehicle against the overloaded vehicles operating on Wisconsin roads in recent years. The evaluation was conducted using three sets of data: 1) overloaded vehicle records within weigh-in-motion data collected in 2007; 2) the single-trip permit application records from 2004 to 2007; and 3) overloaded vehicles in neighboring states, including Minnesota, Iowa, Michigan, and Illinois. Descriptive statistical analyses were conducted for the collected overloaded vehicle data, and model vehicles that represent heavies 5% of the overloaded vehicles were created. The maximum moment/shear in simply supported, 2-span and 3-span continuous girders by the representative vehicles were calculated and compared with the impact of Wis-SPV. The study indicates Wis-SPV envelopes almost all single-unit trucks with less than 9 axles, which attributes 80% of the total permit records. The analysis of WIM records shows that about 0.035% of total overloaded vehicles (records) may exceed the impact of the 250-kip Wis-SPV. A 5-axle short truck was proposed to supplement Wis-SPV for possible use in the WisDOT Bridge Manual.