US Bridges

I 15 over Sep Tintinger

Fair

Cascade County, Montana · 5M S Cascade · Structure no. I00015249+05051

Built
1961
64 years old
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
134 ft
3 main spans
Daily traffic
2,218
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Sep Tintinger is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Sep Tintinger in Cascade County, Montana. It was built in 1961, so it is 64 years old, older than the Montana average of 47 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 2,218 vehicles a day, roughly 16% of them trucks, projected to reach 2,361 by 2043. The structure is 134 ft (40.8 m) long and 47 ft wide.

Location

Open in Google Maps
CarriesI 15
CrossesSep Tintinger
Location5M S Cascade
RouteInterstate 15
CountyCascade County
StateMontana
Coordinates47.20701, -111.78043
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71 US tons
Inventory rating47 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length134 ft (40.8 m)
Longest span52 ft (15.7 m)
Deck width47 ft (14.4 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,218 (2023)
Projected traffic2,361 by 2043
Trucks16%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 over Sep Tintinger built?

It was built in 1961, making it 64 years old in 2025.

What condition is I 15 over Sep Tintinger 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 March 2024.

How much traffic does I 15 over Sep Tintinger carry?

About 2,218 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I 15 over Sep Tintinger?

The structure is 134 ft (40.8 m) long with a longest span of 52 ft (15.7 m) and a deck 47 ft wide.

Who owns I 15 over Sep Tintinger?

It is owned by the State Highway Agency.