US Bridges

Stc 5805;WESTSIDE over Smith Creek

Fair

Boundary County, Idaho · 2.6 S. 2.7 W. Porthill · Structure no. 000000000020740

Built
1970
55 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
103 ft
2 main spans
Daily traffic
80
2023 count
Owner
County
County Highway Agency

About this bridge

Stc 5805;WESTSIDE over Smith Creek is a prestressed concrete stringer/multi-beam or girder carrying Stc 5805;WESTSIDE over Smith Creek in Boundary County, Idaho. It was built in 1970, so it is 55 years old, older than the Idaho average of 45.3 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.

It carries about 80 vehicles a day, roughly 14% of them trucks, projected to reach 120 by 2042. The structure is 103 ft (31.4 m) long and 29 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesStc 5805;WESTSIDE
CrossesSmith Creek
Location2.6 S. 2.7 W. Porthill
RouteCounty Highway 5805
CountyBoundary County
StateIdaho
Coordinates48.96111, -116.55472
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 inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating38 US tons
Inventory rating23 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length103 ft (31.4 m)
Longest span50 ft (15.2 m)
Deck width29 ft (8.8 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic80 (2023)
Projected traffic120 by 2042
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.1 million (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Stc 5805;WESTSIDE over Smith Creek built?

It was built in 1970, making it 55 years old in 2025.

What condition is Stc 5805;WESTSIDE 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 July 2023.

How much traffic does Stc 5805;WESTSIDE over Smith Creek carry?

About 80 vehicles per day (2023 count), of which roughly 14% are trucks.

How long is Stc 5805;WESTSIDE over Smith Creek?

The structure is 103 ft (31.4 m) long with a longest span of 50 ft (15.2 m) and a deck 29 ft wide.

Who owns Stc 5805;WESTSIDE over Smith Creek?

It is owned by the County Highway Agency.