OR 38: Umpqua River Bridge Replacement

This project replaced the 1929, 845-foot-long Umpqua River Bridge on Highway 38. The new structure is a 1,280-foot-long x 47-feet-wide, 7-span steel plate girder bridge with a cast-in-place deck. The bridge is supported by 96-inch-diameter drilled shafts at the piers and the abutments are founded on spread footings. Additional foundation work in the footprint of the abutments includes deep soil cement mixing to mitigate soil liquefaction in the event of seismic activity.

The new bridge structure is constructed downstream of the existing truss. Access for construction activities requires one workbridge that spans the full width of the river. A second full-length workbridge is required for the demolition and removal of the old structure. Staged construction on the project requires three phases where traffic is temporarily placed in a one-way configuration guided by temporary signals and 24-hour flagging.

Structure work on the project includes steel tube bridge railing with ornamental concrete pilasters and pylons at the ends of the bridge, two soldier pile retaining walls with tieback anchors and cast-in-place concrete facing, temporary shoring walls, and cast-in-place concrete headwalls and drainage facilities. 

Major Project Elements

• Multiple work bridges
• 8-foot-diameter shafts
• Deep soil mixing under abutments.
• Large/tall cast in place abutment work.
• 6-foot-square, decorative columns
• Curved and haunched steel girders at both ends
• Large Plate girders spanning middle sections of the bridge
• Cast-in-place deck (10-inch-thick)
• Decorative rail elements
• Demolition of old bridge
• Soldier Pile and tie back walls