US Bridges

S 435 over Smith Creek

FairPosted for load

Lewis and Clark County, Montana · 4M SW Augusta · Structure no. S00435004+02351

Built
1958
67 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
76 ft
3 main spans
Daily traffic
137
2023 count
Owner
County
County Highway Agency

About this bridge

S 435 over Smith Creek is a wood or timber stringer/multi-beam or girder carrying S 435 over Smith Creek in Lewis and Clark County, Montana. It was built in 1958, so it is 67 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 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 137 vehicles a day, roughly 2% of them trucks, projected to reach 144 by 2043. The structure is 76 ft (23.2 m) long and 26 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

CarriesS 435
CrossesSmith Creek
Location4M SW Augusta
RouteCounty Highway 435
StateMontana
Coordinates47.44465, -112.44901
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum 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 alignment8: Equal to present desirable criteria
Operating rating42 US tons
Inventory rating28 US tons

Structure

MaterialWood or Timber
DeckWood or timber
Main spans3
Design loadHS 15
Structure length76 ft (23.2 m)
Longest span25 ft (7.6 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic137 (2023)
Projected traffic144 by 2043
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 S 435 over Smith Creek built?

It was built in 1958, making it 67 years old in 2025.

What condition is S 435 over Smith Creek 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 September 2023.

How much traffic does S 435 over Smith Creek carry?

About 137 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is S 435 over Smith Creek?

The structure is 76 ft (23.2 m) long with a longest span of 25 ft (7.6 m) and a deck 26 ft wide.

Who owns S 435 over Smith Creek?

It is owned by the County Highway Agency.