Old Structures Fill the Gap While New Bridges Built

By Melody Finnemore

When the Oregon Department of Transportation began planning to replace a series of 80-year-old bridges on Oregon 38 between Elkton and Drain, it gave surrounding residents two options. ODOT could either shut down the highway completely for 21 days or narrow it to a single lane for 180 days.

Safety was a key reason for the project’s success. Jeremy Lawson, Slayden vice president of safety, made frequent checks. (Image courtesy of Oregon OSHA)

Though it meant a longer period of disruption, residents preferred to keep at least a single lane open because that stretch of highway serves about 3,000 motorists daily a day. In addition, Oregon 38 is crucial to the tourism and timber industries that support the small coastal towns, as well as freight movement through the region.

This steady flow of both goods and people along the highway was just one of several difficulties the project team faced as they built five new bridges to replace the old ones.

ODOT contractor Slayden Construction of Stayton, Ore., headed the team that devised a strategy to use rapid replacement for two of the bridges to help reduce construction-related delays.

Through this method, which is seldom used in Oregon, most of the replacement bridge is built next to the old one. The old bridge is demolished and the new one is slid into place.

The pair of bridges designated for rapid replacement is located at the portal of a tunnel, one within 38 feet of the portal and the other within 180 feet. The team could not build a temporary structure for the bridge on the east side because of the proximity of the tunnel portal. While there was more room for the bridge on the west side, the team used rapid replaceme

advertisement

nt because of cost efficiencies.

The rapid replacement technique allowed the project team, which included designer T.Y. Lin International and Mammoet to complete skidding two of the new bridges in just two 48-hour windows. The first bridge slide took place last May 9-11 and the second – was completed Sept. 5-7.

The strategy involved fabricating pieces of the structure in advance of the closure. Slayden built supports for each new bridge under the existing structures, and then built new bridges next to the old ones. The team demolished the old bridges and recycled the components. They used Mammoet’s hydraulic skid system to slide the remainder of the old bridge out of the way and slide the 225 foot replacement bridge into place. The team lowered the new bridge onto its foundation and secured it, then connected the roadway to the new bridge.

Larry Gescher, Slayden’s project manager, said his company received the ODOT contract in December 2006 and immediately began designing its plan to replace the bridges. It quickly became apparent that rapid replacement was the way to go.

The finished bridge has improved capacity to allow better freight transport between the Oregon Coast and the Willamette Valley. (Photo courtesy of Slayden Construction)

“The site constraints created some big challenges, and so did the topography of the land because there are some real steep rock cliffs there,” Gescher says. “The access at the project site was very limited, and we just needed to keep the traffic moving at all times. ,” he said. “We didn’t add to the cost by using rapid replacement, but I knew it would be more favorable from a mobility standpoint.”

Steve Narkiewicz, ODOT project manager, said the agency structured the project as a design-build contract in order to generate the most creative solutions possible for a very technically difficult endeavor.

“We specifically selected this as a design-build project because we wanted to see some innovation, especially in terms of how the bridges were going to be built,” he said. “We’ve done probably a dozen design-build contracts, but what was different about this one was that we were able to see what you wanted to see and that is some real innovation around the design and construction,.” he says.

Narkiewicz said the project’s success includes the project team’s effort to build a relationship with the community. “To essentially go out and satisfy a whole bunch of different people with different desires and to do that with someone outside the agency is really tough,” he adds.

With the final bridge replacement due for completion this spring, Slayden’s Gescher said he learned several lessons throughout this unique project, one of which was the importance of public involvement.

“We had a huge PI program on this one. We realized up front we were going to impact the local community, so we needed their involvement and for them to understand what we were going to do,” he adds. “A lot of times, the biggest challenge is getting people to come to the public meetings so you can talk to them about a project.”

“Our team did multiple outreach programs so we could reach a large part of the community and help them understand the project. It paid huge dividends because, during the entire duration of the project, I got one phone call and that was a question rather than a complaint. I believe that was because the public understood the project.” Time lapse videos of both bridge slides are available at www.slayden.com and also on ODOT’s YouTube channel at www.youtube.com/user/oregondot.

Useful Sources

• The bearing pads on Mammoet’s hydraulic skid system are coated in Teflon, just like a non-stick skillet.
• The construction crew used kitchen soap to lubricate the Teflon before the “big slide.”
• By recycling materials from several of the bridges in the Oregon 38 bridge replacement project, ODOT diverted 4,100 tons of concrete and steel from landfills.