As part of a consultant team to ODOT, GRI provided geotechnical engineering services to assist with design of the wider and longer rural, single-span replacement bridge. GRI also provided construction-phase geotechnical services during construction of the bridge and approach fills. The new bridge has a length of about 56 feet and width of 47 feet, and the bridge deck was raised about 3.5 feet. Foundation support for the bridge was provided by 16-inch-diameter driven pipe piles. GRI evaluated subsurface conditions at the site with drilled borings and developed recommendations for design and construction of foundations for the proposed replacement structure, including seismic design considerations. Due to seismic loading and potential deep scour affecting a gravity type retaining wall for support of the approach fills, a tied-back sheetpile wall system with sheetpiles driven below the depth of scour and backfilled lightweight cellular concrete was chosen as the preferred wall alternative. GRI provided recommendations for new and overlay flexible pavements. GRI also provided construction engineering support during construction.

Location: Vernonia, Oregon

Owner: ODOT

Market Sector: Transportation 

Services: Geotechnical Engineering, Geologic Hazards, Seismic Engineering, Construction Services, Pavement Engineering