As industry grows and produces ever-larger items, the use of special purpose oversize and overweight (OSOW) vehicles to transport these items also continues to grow. An overweight vehicle crossing a bridge, even if it is a single crossing, may affect both the short-term behavior of the bridge, but also it’s long-term performance and life-cycle cost. However, special permits are issued by state DOTs to overload vehicles without factoring in these cumulative, long-term effects.
A research team at the University of Wisconsin-Madison led by Dr. Michael Oliva recently completed the second phase of a CFIRE-funded project that analyzed and evaluated the effects of overload vehicles on bridges. This project aimed to help agencies in evaluating the long-term impact of vehicles on bridges so that they can assign the resulting costs to OSOW permit applicants.
Researchers used stress and cycles (S-N) relations and Miner’s damage accumulation rule to calculate the damage to bridge components due to an overload and then used the life-cycle cost of a given bridge component and the damage accumulated to calculate an assigned cost per overload.
The project team applied this process for assigning cost for crossing bridges with overloads to two sets of examples as pilots: 1) two concrete decks and 2) two steel girder bridges.
For more information about this project and to consult the final report, visit the CFIRE 02-03 project page.