Background

The Manning Crevice Bridge was originally built in the 1930s as a Civilian Conservation Corps project, serving as an icon of the scenic Salmon River and providing vital connectivity in a very remote area. The bridge's age and ability to sustain load had greatly diminished, requiring it to be replaced to extend and preserve its function.

Project Details

Horrocks designed the roadway and retaining wall, developing an alignment for a one-lane, asymmetrical suspension bridge spanning more than 300 feet. The structure has a 75-foot-tall tower on the north end, increased deck width, and greater load capacity.

Because of its location, this project had a significant number of high-risk elements that required specialized construction methods and had multiple environmental and local resources that needed to be protected. Native American trails, the Wild and Scenic River status, diverse wildlife around the bridge, and the historic original retaining walls and structures were just a few of the environmental elements needing protection.

Outcomes

In addition to preserving a historic landmark, this project restored safe passage and functionality for this bridge. The area is again open to sightseers and commercial users, and larger emergency vehicles such as fire trucks and ambulances have the necessary clearance to safely cross the bridge. This improved access allows for faster emergency services and enhanced forest management.  

Awards:

American Institution of Steel Construction (AISC) / National Steel Bridge Alliance (NSBA), National Prize Bridge Award, 2020