91ÊÓƵ

Deep in the Oregon wilds, near the coastal range, the last week unveiled the new Elkton Bridge that crosses Elk Creek on Oregon Highway 38.
The new structures, extending 222 feet and weighing 2.5 million pounds, were completed using a unique method of bridge replacement called bridge jacking that drastically reduced the time the bridge spans were closed from six months to six days.

Bridge jacking is a rapid bridge replacement technique that’s not often used in the United States. However, it is a common practice in Europe, where companies specialize in the procedure. Crews build a new bridge next to the soon-to-be-demolished bridge. The old bridge then remains open during construction and isn’t demolished until it is necessary to do so.

Once the new bridge is completed, move the old bridge out of the way, and the new bridge takes its place.

If this had been any other project, ODOT would have simply constructed a temporary bridge, said Thomas Lauer, the branch manager for major projects for ODOT.

But the Elkton Bridge rests on opposite ends of a tunnel – so close, in fact, to the entrance and exit points as to make the alignment of temporary bridges impossible.

The project’s general contractor, , worked with specialty contractor , a Dutch company that pioneered the development and use of hydraulic skidding systems and other devices for heavy lifting.

The company’s name means “mammoth” in Dutch.

And perhaps the most difficult aspect of the project, according to ODOT, was determining how to connect the bridge to its substructure, once moved, and thus secure it to its final position. After the west-side bridge was installed, crews spent a significant amount of time aligning the bridge on the substructure and ensuring that it met ODOT’s strict seismic activity standards.
Lauer considers the complicated project a partnership between the community, transportation officials and the numerous contractors involved.

“Obviously, when you look at the typical scenario (with these bridges), we’d have to go out and demolish and reconstruct them in place,” Lauer said. “That would have a tremendous effect on the community and its corridor.”

As part of the partnership with the community, ODOT engaged local students by going to area schools and teaching them about bridge engineering.

There was even a design competition for students. Through the competition, the young artists were asked to submit their designs for colored carvings to accentuate the bridges’ pylons; the winning submission earned $500.

There were two winners: Richard Sanchez, who designed three of the four carvings, and Jackson Murphy who came up with the final design. Wood carvers from in Roseburg worked on that aspect of the project.

“We’re trying to do it as close to what they want as possible,” said Peter Pappas, a project manager for the company, which specializes in carvings and masonry work.

In addition to Victory Builders, Slayden and Mammoet, subconsultant also worked on the project, mapping out its sometimes complicated design and construction schedule.

“There’s nothing wholly exotic about the final bridges,” Lauer said. “But what is exotic is we were able to put them in place with no disruption to the community.”