US Bridges

I 15 over Silverbow Creek-Rr

Good

Silver Bow County, Montana · 1.2 N W Butte · Structure no. 000000201901107

Built
2019
6 years old
Condition
Good
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
598 ft
4 main spans
Daily traffic
7,379
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Silverbow Creek-Rr is a steel stringer/multi-beam or girder carrying I 15 over Silverbow Creek-Rr in Silver Bow County, Montana. It was built in 2019, so it is 6 years old, younger 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 7,379 vehicles a day, roughly 15% of them trucks, projected to reach 7,747 by 2043. The structure is 598 ft (182.3 m) long and 40 ft wide.

Location

Open in Google Maps
CarriesI 15
CrossesSilverbow Creek-Rr
Location1.2 N W Butte
RouteInterstate 15
CountySilver Bow County
StateMontana
Coordinates45.9962, -112.5632
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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable 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 alignment7: Better than present minimum criteria
Operating rating66 US tons
Inventory rating51 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length598 ft (182.3 m)
Longest span165 ft (50.3 m)
Deck width40 ft (12.2 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,379 (2023)
Projected traffic7,747 by 2043
Trucks15%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad and waterway
Detour if closed—
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 15 over Silverbow Creek-Rr built?

It was built in 2019, making it 6 years old in 2025.

What condition is I 15 over Silverbow Creek-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 September 2023.

How much traffic does I 15 over Silverbow Creek-Rr carry?

About 7,379 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is I 15 over Silverbow Creek-Rr?

The structure is 598 ft (182.3 m) long with a longest span of 165 ft (50.3 m) and a deck 40 ft wide.

Who owns I 15 over Silverbow Creek-Rr?

It is owned by the State Highway Agency.