Under our on-call contract with Clark County, GRI provided geotechnical and pavement services for this project. Improvements included reconfiguration of the roadway at three locations, new retaining walls, three new box culverts beneath the road to permit fish passage, underground utilities, stormwater facilities, and reconstructed pavements. GRI characterized subsurface conditions along the alignment with a series of soil borings and completed four, small-scale Pilot Infiltration Tests to evaluate the feasibility of infiltrating stormwater on the project. Recommendations were provided for earthwork, seismic design considerations, culvert foundations, retaining walls, stormwater infiltration, and pavement design. The geotechnical and pavement investigations were completing in accordance with Washington Department of Transportation (WSDOT) Local Agency Guidelines (LAG) guidelines.

Location: Longview, Washington

Owner: Clark County

Market Sector: Transportation, Water & Environment

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