North Fork Kalama River Culvert
Owner: Weyerhaeuser Company
Project Location: Castle Rock, Washington
Engineering Service: Bridge Engineering
McGee Engineering was the primary designer for replacing a failed log stringer bridge in the headwaters of the North Fork Kalama River. The site posed significant alignment constraints with a channel confluence just downstream of the historic crossing, steep road approaches into the site, a tight horizontal curve to the road, and bedrock visible in existing road cut banks. The site was also extremely remote with difficult haul access and a very tight construction window controlled by snow.
Due to the road’s horizontal alignment and inability to ship large materials to the site, a large deep corrugation culvert/buried bridge was selected for the final structure. The culvert provided a 34′ interior span and 21′ interior rise using cast-in-place concrete footings. To minimize the length required for the crossing, MSE wire headwalls were used to provide field flexibility for actual bedrock conditions encountered and to use local sourced material given the remote nature of the project.
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