US Bridges

US101 (hwy 9) over Alsea Bay

Fair

Lincoln County, Oregon · In City of Waldport · Structure no. 01746B009 15554

Built
1992
33 years old
Condition
Fair
inspected July 2024
Type
Arch - Thru
Steel
Length
2,910 ft
1 main span
Daily traffic
8,975
2022 count
Owner
State
State Highway Agency

About this bridge

US101 (hwy 9) over Alsea Bay is a steel arch - thru carrying US101 (hwy 9) over Alsea Bay in Lincoln County, Oregon. It was built in 1992, so it is 33 years old, younger than the Oregon average of 49.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 8,975 vehicles a day, roughly 5% of them trucks, projected to reach 9,500 by 2042. The structure is 2,910 ft (887 m) long and 80 ft wide. If it were closed, the detour would be 81.4 mi (131 km).

Location

Open in Google Maps
CarriesUS101 (hwy 9)
CrossesAlsea Bay
LocationIn City of Waldport
RouteU.S. Route 101
CountyLincoln County
StateOregon
Coordinates44.43194, -124.07035
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeArch - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+13 approach)
Design loadHS 25 or greater
Structure length2,910 ft (887 m)
Longest span450 ft (137.2 m)
Deck width80 ft (24.4 m)
Roadway width64 ft (19.5 m)
Vertical clearance over deck30 ft (9.2 m)

Traffic and service

Average daily traffic8,975 (2022)
Projected traffic9,500 by 2042
Trucks5%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed81.4 mi (131 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US101 (hwy 9) over Alsea Bay built?

It was built in 1992, making it 33 years old in 2025.

What condition is US101 (hwy 9) over Alsea Bay in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2024.

How much traffic does US101 (hwy 9) over Alsea Bay carry?

About 8,975 vehicles per day (2022 count), of which roughly 5% are trucks.

How long is US101 (hwy 9) over Alsea Bay?

The structure is 2,910 ft (887 m) long with a longest span of 450 ft (137.2 m) and a deck 80 ft wide.

Who owns US101 (hwy 9) over Alsea Bay?

It is owned by the State Highway Agency.