US Bridges

Stc 7787;PLYMOUTH over Riverside Canal

Fair

Canyon County, Idaho · In Caldwell;plymouth ST · Structure no. 000000000026835

Built
1930
95 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Concrete
Length
27 ft
1 main span
Daily traffic
2,100
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Stc 7787;PLYMOUTH over Riverside Canal is a concrete stringer/multi-beam or girder carrying Stc 7787;PLYMOUTH over Riverside Canal in Canyon County, Idaho. It was built in 1930, so it is 95 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 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 2,100 vehicles a day, roughly 6% of them trucks, projected to reach 3,150 by 2042. The structure is 27 ft (8.2 m) long and 31 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesStc 7787;PLYMOUTH
CrossesRiverside Canal
LocationIn Caldwell;plymouth ST
RouteCity Street 7787
CountyCanyon County
StateIdaho
Coordinates43.68888, -116.6855
Functional classUrban 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.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating61 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length27 ft (8.2 m)
Longest span25 ft (7.6 m)
Deck width31 ft (9.5 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,100 (2023)
Projected traffic3,150 by 2042
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$479,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Stc 7787;PLYMOUTH over Riverside Canal built?

It was built in 1930, making it 95 years old in 2025.

What condition is Stc 7787;PLYMOUTH over Riverside Canal 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 February 2024.

How much traffic does Stc 7787;PLYMOUTH over Riverside Canal carry?

About 2,100 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is Stc 7787;PLYMOUTH over Riverside Canal?

The structure is 27 ft (8.2 m) long with a longest span of 25 ft (7.6 m) and a deck 31 ft wide.

Who owns Stc 7787;PLYMOUTH over Riverside Canal?

It is owned by the City or Municipal Highway Agency.