When a major storm hit Whatcom County, Wash., in 2009, it caused serious damage. Erosion damaged a roadway and bridge structure, blocking access to a diversion dam critical to maintaining a clean water source for the city of Bellingham.
Restoring access was a major priority for the county, and finding a solution to replace the washed-out bridge in a timely fashion was crucial.
For a long-term solution, the city turned to GeoEngineers Inc. The bridge required abutments and wing walls, for which Geoengineers recommended “only Redi-Rock walls, because they are unique in that they are large blocks that have a positive connection between the geogrid and the block itself,” said the engineering report. “The big blocks and positive connection provide the greatest resistance under these circumstances for the lowest cost.”
Installation of the upper walls was completed just two weeks from the time excavation started to the time traffic was running over the bridge.
On the lower walls, engineers “arrived at a gravity system because of the shorter height requirement. Using gravity walls allowed us to reduce excavation on that portion of the project, because we didn’t have to cut the slope back as far,” said Aaron Hartvigsen, P.E., of GeoEngineers Inc.
The ability to utilize both gravity and reinforced walls on the same project is a major benefit of the Redi-Rock system. In total, this project required 1,750 sq ft of Redi-Rock walls, up to 15 ft high.
Download: Here
