The City of Portland and the US Army Corps of Engineers are partnered to complete a habitat restoration project at the Oaks Bottom Wildlife Refuge in Portland, Oregon. The project included replacement of an existing 5-foot diameter concrete culvert with a new pre-fabricated open-bottom arch culvert as part of tidal restoration and habitat enhancement project benefiting salmon and other wildlife. The culvert extends beneath an existing railroad embankment that separates Oaks Bottom from the Willamette River.
SERVICE: Foundation Engineering was retained by the contractor (K&E Excavating) to provide geotechnical recommendations for the design of MSE wing walls and a bump out wall and for preparing the subgrade beneath the culvert and wing wall foundations. Foundation Engineering was on site during the foundation preparation and worked with the contractor, City, and USACE to develop an approach for mitigating soft, wet subgrade conditions by excavating and immediately backfilling the subgrade rock with stabilization rock in short segments. This approach helped the project stay on schedule.