ODOT project to address Hwy. 20 bridge over slide area

The Oregon Department of Transportation said Tuesday it plans a two-year, two-phase project to address earth movement, and bridge and highway damage from an active landslide on the east end of the Sheep Creek Bridge, about 25 miles east of Sweet Home.

The Sheep Creek Bridge was built with its eastern abutment located on an active slide, officials said.

When the bridge was replaced in 1962, the new bridge was designed to accommodate slide movement and be adjusted as the earth around it moved. In 1993, 2006 and 2011, the east abutment was adjusted for the movement.

Until about 2010, the earth movement was measured at about one inch per year. For the past four years, however, the movement has increased to six to seven inches per year.

ODOT said the project “won’t change the need for the bridge to continue to accommodate earth movement.

“But this project is designed to redirect and reduce the slide activity so that the impact to the bridge will be consistent and predictable, and therefore, more manageable,” the agency said.

Phase 1, to be constructed this summer, will construct a row of 16 columns, reaching 50 feet below the ground surface along the north side of the bridge.

The columns will consist of large, steel piles embedded vertically in four-foot diameter cylinders of concrete. The row of columns, similar to a buried picket fence, is designed to re-direct the slide away from the bridge.

Phase 2, to be constructed in the summer of 2016, will repair slide damage to the bridge, and reset the bridge on the eastern abutment.

Travel Impacts:

Phase 1–July-October, 2015:

–Intermittent single lane restrictions

–Flaggers controlling travel

–Delays as long as 45 minutes.

Phase 2 –Summer-fall, 2016

–Travel impacts won’t be known until late 2015, after plans and design are finalized.

For more information, visit the project Website.

The US 20: Sheep Creek Bridge project was identified during development of the South Santiam Forest Corridor, an Oregon Solutions collaborative effort involving partners from agencies of federal, state, county, tribal and local governments, as well as representatives from private industry and non-profits.

You can learn more about the South Santiam Forest Corridor and Oregon Solutions by visiting http://orsolutions.org/osproject/SSCFC .