Chetco River Bridge
GRI provided geotechnical services to the Western Federal Lands Highway Division (WFLHD) for repair and rehabilitation of U.S. Forest Service Upper Chetco River Bridge. The project improved surface water drainage and lower seasonally high groundwater levels to improve slope stability, relieve lateral earth pressures behind the north end of the bridge, provide deep foundation support for an existing pier and a new end bent, replace and lengthen the northern end span, as well as other repairs and improvements to the bridge superstructure. GRI completed a preliminary geotechnical investigation to evaluate design of rehabilitation alternatives, during which it was concluded that deep-seated slope movement of the north riverbank has resulted in the transfer of large lateral forces to the bridge superstructure and foundations. GRI provided lateral earth pressure criteria and design recommendations for deep foundations and evaluated stability of slopes during seismic conditions. The work included installation and monitoring of instrumentation to record groundwater levels and detect slope movement behind the north end of the bridge.
Location: Brookings, Oregon
Owner: Western Federal Lands Highway Division