US Bridges

Portal Creek Road over Portal Creek

Good

Gallatin County, Montana · No Data Entered · Structure no. 011106000003014

Built
2005
20 years old
Condition
Good
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
50 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

Portal Creek Road over Portal Creek is a steel stringer/multi-beam or girder carrying Portal Creek Road over Portal Creek in Gallatin County, Montana. It was built in 2005, so it is 20 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 50 ft (15.2 m) long and 16 ft wide. If it were closed, the detour would be 620.7 mi (999 km).

Location

Open in Google Maps
CarriesPortal Creek Road
CrossesPortal Creek
LocationNo Data Entered
RouteFederal Lands Road 984
CountyGallatin County
StateMontana
Coordinates45.29475, -111.13946
Functional classRural Local

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 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating25.4 US tons
Inventory rating19.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span49 ft (14.8 m)
Deck width16 ft (4.8 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (—)
Projected traffic75 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed620.7 mi (999 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Portal Creek Road over Portal Creek built?

It was built in 2005, making it 20 years old in 2025.

What condition is Portal Creek Road over Portal Creek 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 2024.

How much traffic does Portal Creek Road over Portal Creek carry?

About 50 vehicles per day (latest count).

How long is Portal Creek Road over Portal Creek?

The structure is 50 ft (15.2 m) long with a longest span of 49 ft (14.8 m) and a deck 16 ft wide.

Who owns Portal Creek Road over Portal Creek?

It is owned by the U.S. Forest Service.