Structure 19726 · Canyon County, ID

Stc 3750;middleton over Boise River

Carries Stc 3750;middleton over Boise River, 0.6 S. 0.3 E. Middleton.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT433 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

433 ft end to end, longest span 83 ft: about 6 semi-trucks nose to tail. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built200422 years old
Length433.1 ft132 m
Daily traffic11,000counted 2023
Last inspectedNovember 2024every 48 months

Location

StateIdaho
CountyCanyon
Location0.6 S. 0.3 E. Middleton
CarriesStc 3750;middleton
CrossesBoise River
Coordinates43.69622, -116.61283

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length433.1 ft (132 m)
Max Span83.0 ft (25.3 m)
Deck Width53.1 ft (16.2 m)
Deck Area2138.4 sq m
Main Spans5
Year Built2004

Traffic

Avg Daily Traffic11,000 (2023)
Truck Traffic9%
Lanes On Bridge2

Inspection & Ownership

Last InspectionNovember 2024
Inspection FrequencyEvery 48 months
OwnerOther Local Agencies
Historical SignificanceHistorical significance is not determined
Scour Critical8 — Stable, low risk
Structure Number000000000019726

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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