US Bridges

Seward Highway over Portage Creek No 2

Good

Anchorage Municipality, Alaska · Mile Point 78.6 · Structure no. 0631

Built
2023
2 years old
Condition
Good
inspected February 2024
Type
Tee Beam
Prestressed Concrete
Length
290 ft
2 main spans
Daily traffic
5,160
2020 count
Owner
State
State Highway Agency

About this bridge

Seward Highway over Portage Creek No 2 is a prestressed concrete tee beam carrying Seward Highway over Portage Creek No 2 in Anchorage Municipality, Alaska. It was built in 2023, so it is 2 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 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 5,160 vehicles a day, roughly 14% of them trucks, projected to reach 6,030 by 2039. The structure is 290 ft (88.4 m) long and 66 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

CarriesSeward Highway
CrossesPortage Creek No 2
LocationMile Point 78.6
RouteInterstate 0A31
StateAlaska
Coordinates60.827, -148.97806
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

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

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation9: Superior to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating103.5 US tons
Inventory rating61.9 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckOther
Main spans2
Design loadHL 93
Structure length290 ft (88.4 m)
Longest span141 ft (43.1 m)
Deck width66 ft (20.2 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,160 (2020)
Projected traffic6,030 by 2039
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
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 Portage Creek No 2 built?

It was built in 2023, making it 2 years old in 2025.

What condition is Seward Highway over Portage Creek No 2 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 February 2024.

How much traffic does Seward Highway over Portage Creek No 2 carry?

About 5,160 vehicles per day (2020 count), of which roughly 14% are trucks.

How long is Seward Highway over Portage Creek No 2?

The structure is 290 ft (88.4 m) long with a longest span of 141 ft (43.1 m) and a deck 66 ft wide.

Who owns Seward Highway over Portage Creek No 2?

It is owned by the State Highway Agency.