US Bridges

Frontage Rd-S 205 over Gallatin River

Fair

Gallatin County, Montana · 3M SE Manhattan · Structure no. S00205014+05181

Built
1949
76 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
252 ft
3 main spans
Daily traffic
3,038
2023 count
Owner
State
State Highway Agency

About this bridge

Frontage Rd-S 205 over Gallatin River is a steel continuous stringer/multi-beam or girder carrying Frontage Rd-S 205 over Gallatin River in Gallatin County, Montana. It was built in 1949, so it is 76 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 3,038 vehicles a day, roughly 1% of them trucks, projected to reach 3,190 by 2043. The structure is 252 ft (76.8 m) long and 32 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

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CarriesFrontage Rd-S 205
CrossesGallatin River
Location3M SE Manhattan
RouteState Highway 205
CountyGallatin County
StateMontana
Coordinates45.82503, -111.27167
Functional classRural Major Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating56.3 US tons
Inventory rating43.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length252 ft (76.8 m)
Longest span95 ft (29 m)
Deck width32 ft (9.8 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,038 (2023)
Projected traffic3,190 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 km)
TollOn a free road
National Highway SystemNo

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 Frontage Rd-S 205 over Gallatin River built?

It was built in 1949, making it 76 years old in 2025.

What condition is Frontage Rd-S 205 over Gallatin River 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 April 2024.

How much traffic does Frontage Rd-S 205 over Gallatin River carry?

About 3,038 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is Frontage Rd-S 205 over Gallatin River?

The structure is 252 ft (76.8 m) long with a longest span of 95 ft (29 m) and a deck 32 ft wide.

Who owns Frontage Rd-S 205 over Gallatin River?

It is owned by the State Highway Agency.