US Bridges

Seward Highway over Bird Creek

Fair

Anchorage Municipality, Alaska · Mile Point 100.7 · Structure no. 0643

Built
1950
75 years old, rebuilt 1983
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
204 ft
3 main spans
Daily traffic
6,860
2020 count
Owner
State
State Highway Agency

About this bridge

Seward Highway over Bird Creek is a steel stringer/multi-beam or girder carrying Seward Highway over Bird Creek in Anchorage Municipality, Alaska. It was built in 1950 and reconstructed in 1983, so it is 75 years old, older than the Alaska average of 35.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 6,860 vehicles a day, roughly 8% of them trucks, projected to reach 7,820 by 2039. The structure is 204 ft (62.2 m) long and 55 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesSeward Highway
CrossesBird Creek
LocationMile Point 100.7
RouteInterstate 0A31
CountyAnchorage Municipality
StateAlaska
Coordinates60.97306, -149.46694
Functional classRural Principal Arterial - Interstate

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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating62.4 US tons
Inventory rating37.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length204 ft (62.2 m)
Longest span79 ft (24.1 m)
Deck width55 ft (16.9 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,860 (2020)
Projected traffic7,820 by 2039
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Seward Highway over Bird Creek built?

It was built in 1950, making it 75 years old in 2025. It was reconstructed in 1983.

What condition is Seward Highway over Bird Creek 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 June 2023.

How much traffic does Seward Highway over Bird Creek carry?

About 6,860 vehicles per day (2020 count), of which roughly 8% are trucks.

How long is Seward Highway over Bird Creek?

The structure is 204 ft (62.2 m) long with a longest span of 79 ft (24.1 m) and a deck 55 ft wide.

Who owns Seward Highway over Bird Creek?

It is owned by the State Highway Agency.