Crabtree Creek (Gilkey Road) Bridge

Linn County Road Department plans to replace the existing bridge crossing Crabtree Creek on Gilkey Road in Linn County.  The current structure is a ±133‑foot long, three‑span, reinforced concrete girder bridge supported by timber piling.  The bridge is structurally deficient due to an inventory load rating of 9 tons and the presence of shear cracks in the girders, and is functionally obsolete due to its narrow width. 

The replacement bridge will be a ±142‑foot long, single‑span, pre‑stressed concrete structure constructed slightly downstream (west) of the existing one.  The road elevation of the new bridge and approaches will be raised up to ±5 feet above existing road grades.  Total fill heights of up to ±10 feet will be required to widen the roadway to the west.  The new bridge will be supported by PP16x0.5 piles driven into dense alluvium.  Sheet piles will be used to protect the bridge abutment walls and wing walls from scour.  However, the presence of dense to very dense gravels present driving challenges.