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‎Highlighted Project:‎ ‎ ‎ ‎ ‎ ‎‎ U.S. 101: Astoria-Megler Bridge (Columbia River)







Project Details

Details

County:  Clatsop

Nearest City:  Astoria

Highway Name/Number: 009 - Oregon Coast

Milepoints: 2.73 - 3.2

Future Cost Range:  $40 million - $70 million

Funding Category: Bridge

Anticipated Programming: 2031-2037

Area Commission on Transportation: NW ACT

Region: 2

Community Benefits

 Safety

 State of Good Repair

Recommended Action

Perform structural inlay or overlay of the bridge deck.

Project Description

The Astoria-Megler Bridge is a critical transportation link between Oregon and Washington and serves as a vital corridor for freight, commerce, emergency response, and regional travel.

The Astoria-Megler is the longest continuous truss bridge in North America at over four miles long. The structure includes 140 spans in the water - by comparison, the average Oregon bridge has two to three spans. On average, the bridge carries more than 9,000 vehicles daily.

While the deck is currently rated in fair condition, inspection results identified areas of cracked, chipped, and flaking concrete caused by spalling, exposed reinforcing steel, and areas with insufficient concrete coverage to adequately protect the steel from the bridge's aggressive marine environment.

For the portion of this deck currently in design, 40% of the deck area requires aggressive partial-depth removal and repair. This is due to salt air penetrating deep into the concrete bridge deck reaching the steel reinforcement and causing rust. Rust makes the steel swell, causing cracks and breaks in concrete from the inside out. Inspection results demonstrate that corrosion-related deterioration is active and widespread.

Rehabilitating this section of the bridge deck is a cost-effective preservation strategy that addresses deterioration before it accelerates further. Timely intervention will slow the corrosion, extend the deck's service life, reduce future maintenance needs, and avoid the substantially higher costs associated with more extensive repairs or deck replacement in the future.

Desired Project Outcome

The primary goal is to maintain a safe functional connection between Oregon and Washington. The secondary goal is to keep the bridge in a state of good repair to avoid having to replace it.

If the bridge deteriorates into poor condition, it would significantly impact freight movement between Oregon and Washington and would limit passenger vehicle travel between the states.