Highway Bridge Design Load and Locality of Truck Loads

摘要

This paper presents the results of a study focusing on the locality of truck loads and examines the adequacy of current design loads for bridge sites in the state of Michigan, US. The structural reliability index is calculated here for a randomly selected bridge sample from the Michigan bridge inventory. Weigh-in-motion truck load data collected in Michigan are used to statistically characterize truck load effect in the bridges' primary members for moment and shear at critical sections. It is found that many of these members' reliability indices are lower than the target value of 3.5 used for the AASHTO LRFD design code calibration. It is concluded that the Michigan bridge design load is inadequate for the target level of safety in the area where the load data were gathered.