US Bridges

US 87 over Otter Creek

Poor

Cascade County, Montana · 6M SE Belt · Structure no. P00057003+00971

Built
1959
66 years old
Condition
Poor
inspected June 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
103 ft
2 main spans
Daily traffic
2,314
2023 count
Owner
State
State Highway Agency

About this bridge

US 87 over Otter Creek is a prestressed concrete stringer/multi-beam or girder carrying US 87 over Otter Creek in Cascade County, Montana. It was built in 1959, so it is 66 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 2,314 vehicles a day, roughly 15% of them trucks, projected to reach 2,430 by 2043. The structure is 103 ft (31.4 m) long and 31 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

CarriesUS 87
CrossesOtter Creek
Location6M SE Belt
RouteU.S. Route 87
StateMontana
Coordinates47.31645, -110.84985
Functional classRural Principal Arterial - Other

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating77.1 US tons
Inventory rating51 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length103 ft (31.4 m)
Longest span51 ft (15.5 m)
Deck width31 ft (9.6 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,314 (2023)
Projected traffic2,430 by 2043
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 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 US 87 over Otter Creek built?

It was built in 1959, making it 66 years old in 2025.

What condition is US 87 over Otter Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in June 2024.

How much traffic does US 87 over Otter Creek carry?

About 2,314 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is US 87 over Otter Creek?

The structure is 103 ft (31.4 m) long with a longest span of 51 ft (15.5 m) and a deck 31 ft wide.

Who owns US 87 over Otter Creek?

It is owned by the State Highway Agency.