The Oregon Department of Transportation (ODOT) will ban heavy-haul trucks from three bridges carrying I-5 over the McKenzie and Willamette Rivers in the Eugene area beginning March 5.
The restriction only affects trucks that operate with special permits that allow them to carry loads over 80,000 lb on Oregon highways. In this case it allows vehicles to cross the bridges only if loaded at or under 20,000 lb per single axle, 34,000 lb per tandem axle and a total gross vehicle weight at or under 105,500 lb.
ODOT engineers have been monitoring deep cracks, called shear cracks, in the beams supporting the bridge decks and decided to place the restrictions after noticing further deterioration. The cracks are similar to those found in the support beams of 1950s-1960s bridges built throughout Oregon. The twin McKenzie bridges were built in 1959, the single Willamette River Bridge in 1962.
"Removing heavy-haul truck loads from these bridges will allow us to keep this section of I-5 open to most traffic," said Don Ehrich, ODOT district maintenance manager. "We are confident that this is the appropriate action to take to keep the bridges safe and sound until they can be replaced."