US Bridges

Irr:airport Road over Seldovia Slough

Fair

Kenai Peninsula Borough, Alaska · Mile Point 0.1 · Structure no. 1017

Built
1979
46 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
181 ft
3 main spans
Daily traffic
340
2020 count
Owner
State
State Highway Agency

About this bridge

Irr:airport Road over Seldovia Slough is a wood or timber stringer/multi-beam or girder carrying Irr:airport Road over Seldovia Slough in Kenai Peninsula Borough, Alaska. It was built in 1979, so it is 46 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 340 vehicles a day, roughly 6% of them trucks, projected to reach 390 by 2039. The structure is 181 ft (55.2 m) long and 34 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesIrr:airport Road
CrossesSeldovia Slough
LocationMile Point 0.1
RouteState Highway 434
CountyKenai Peninsula Borough
StateAlaska
Coordinates59.43694, -151.70889
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating50.7 US tons
Inventory rating32.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans3
Design loadHS 20
Structure length181 ft (55.2 m)
Longest span60 ft (18.3 m)
Deck width34 ft (10.4 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic340 (2020)
Projected traffic390 by 2039
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

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 Irr:airport Road over Seldovia Slough built?

It was built in 1979, making it 46 years old in 2025.

What condition is Irr:airport Road over Seldovia Slough 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 August 2023.

How much traffic does Irr:airport Road over Seldovia Slough carry?

About 340 vehicles per day (2020 count), of which roughly 6% are trucks.

How long is Irr:airport Road over Seldovia Slough?

The structure is 181 ft (55.2 m) long with a longest span of 60 ft (18.3 m) and a deck 34 ft wide.

Who owns Irr:airport Road over Seldovia Slough?

It is owned by the State Highway Agency.