US Bridges

Irr:airport Beach over South Channel Unalaska

Good

Aleutians West Census Area, Alaska · Mile Point 0.7 · Structure no. 1386

Built
2008
17 years old
Condition
Good
inspected September 2024
Type
Tee Beam
Prestressed Concrete
Length
700 ft
5 main spans
Daily traffic
3,450
2020 count
Owner
State
State Highway Agency

About this bridge

Irr:airport Beach over South Channel Unalaska is a prestressed concrete tee beam carrying Irr:airport Beach over South Channel Unalaska in Aleutians West Census Area, Alaska. It was built in 2008, so it is 17 years old, younger than the Alaska average of 35.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 3,450 vehicles a day, roughly 17% of them trucks, projected to reach 5,220 by 2039. The structure is 700 ft (213.4 m) long and 44 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesIrr:airport Beach
CrossesSouth Channel Unalaska
LocationMile Point 0.7
RouteState Highway 310
CountyAleutians West Census Area
StateAlaska
Coordinates53.87422, -166.54668
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110.1 US tons
Inventory rating62.7 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckOther
Main spans5
Design loadHL 93
Structure length700 ft (213.4 m)
Longest span140 ft (42.7 m)
Deck width44 ft (13.3 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,450 (2020)
Projected traffic5,220 by 2039
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byCity or Municipal 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 Irr:airport Beach over South Channel Unalaska built?

It was built in 2008, making it 17 years old in 2025.

What condition is Irr:airport Beach over South Channel Unalaska in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2024.

How much traffic does Irr:airport Beach over South Channel Unalaska carry?

About 3,450 vehicles per day (2020 count), of which roughly 17% are trucks.

How long is Irr:airport Beach over South Channel Unalaska?

The structure is 700 ft (213.4 m) long with a longest span of 140 ft (42.7 m) and a deck 44 ft wide.

Who owns Irr:airport Beach over South Channel Unalaska?

It is owned by the State Highway Agency and maintained by the City or Municipal Highway Agency.