US Bridges

Branch I 15-U.S. 8 over RR

Good

Cascade County, Montana · Great Falls · Structure no. I00315001+00691

Built
1946
79 years old, rebuilt 1996
Condition
Good
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
178 ft
3 main spans
Daily traffic
6,326
2023 count
Owner
State
State Highway Agency

About this bridge

Branch I 15-U.S. 8 over RR is a steel continuous stringer/multi-beam or girder carrying Branch I 15-U.S. 8 over RR in Cascade County, Montana. It was built in 1946 and reconstructed in 1996, so it is 79 years old, older than the Montana average of 47 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 6,326 vehicles a day, roughly 5% of them trucks, projected to reach 6,642 by 2043. The structure is 178 ft (54.2 m) long and 48 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesBranch I 15-U.S. 8
CrossesRR
LocationGreat Falls
RouteInterstate 315
CountyCascade County
StateMontana
Coordinates47.48777, -111.33531
Functional classUrban 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating35.1 US tons
Inventory rating26.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length178 ft (54.2 m)
Longest span67 ft (20.4 m)
Deck width48 ft (14.5 m)
Roadway width45 ft (13.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,326 (2023)
Projected traffic6,642 by 2043
Trucks5%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.2 mi (2 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$755,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was Branch I 15-U.S. 8 over RR built?

It was built in 1946, making it 79 years old in 2025. It was reconstructed in 1996.

What condition is Branch I 15-U.S. 8 over RR 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 May 2023.

How much traffic does Branch I 15-U.S. 8 over RR carry?

About 6,326 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Branch I 15-U.S. 8 over RR?

The structure is 178 ft (54.2 m) long with a longest span of 67 ft (20.4 m) and a deck 48 ft wide.

Who owns Branch I 15-U.S. 8 over RR?

It is owned by the State Highway Agency.