GRI provided geotechnical engineering services to assist with the design of the wider and longer single-span replacement bridge. The new bridge will have a length of about 80 feet and width of 40 feet, and the bridge deck will be raised about 5 feet to replace the five-span, pile-supported timber bridge over Wapato Creek. Foundation support for the bridge will be provided by 16-inch-diameter driven pipe piles. Sheetpiles will be constructed to mitigate scour at the bridge abutments. GRI evaluated subsurface conditions at the site with drilled borings and cone penetration testing to characterize subgrade conditions and develop recommendations for bridge foundations; seismic design; retaining wall design; new asphalt concrete pavement sections; and earthwork. GRI also provided construction engineering support during construction.

Location: Gaston, Oregon

Owner: Washington County

Market Sector:  Transportation

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