Wadsworth Brothers Construction replaced four bridges on 1-80 in Parley’s Canyon, east of Salt Lake City, in two weekends in mid-August 2008. The extensive process was completed in just 37 hours. “It’s the fastest bridge replacement I’ve ever heard of,” said Deryl Mayhew, UDOT resident engineer on the project.
Wadsworth proposed using SPMTs after it won the design-build job. “We were given the choice to do it by having bypass roads and diverting traffic on I-80 around the bridges and doing it at our own pace,” said Guy Wadsworth, President. “We figured the geometry wouldn’t work, so at the last minute we decided to use SPMTs. We had to put together a plan in five days.”
The new approach slabs for the four structures were built adjacent to the existing bridges. Casting included post-tensioning ducts that were embedded in the monolithic slabs with reinforcing steel. After the slabs cured, they were cut into segments, lifted into their final positions and post-tensioned together.
The four approach slabs each weighed about 54,000 pounds. It was difficult to replace approach slabs. The grad had to be nearly perfect to set them.
Historically, these types of construction methods would have caused traffic delays up to an hour in each direction, with a six-month schedule. Using SPMTs saved 190,000 hours of delays, which equates to over $2.5 million.