Structure 57002100.1023A · Jackson County, CO

County Road 21 over Michigan River

Carries County Road 21 over Michigan River, 0.1 Mi W Of ST HWY 14.

Overall conditionFair

Set by its lowest-rated component: Superstructure and Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT51 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 6/9 · sets the rating

51 ft end to end, longest span 39 ft. Lengths and the car 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.

Built198343 years old
Length50.9 ft15.5 m
Daily traffic158counted 2023
Last inspectedNovember 2024every 24 months

Location

StateColorado
CountyJackson
Location0.1 Mi W Of ST HWY 14
CarriesCounty Road 21
CrossesMichigan River
Coordinates40.52589, -106.02864

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length50.9 ft (15.5 m)
Max Span39.0 ft (11.9 m)
Deck Width24.9 ft (7.6 m)
Deck Area117.8 sq m
Main Spans3
Year Built1983

Traffic

Avg Daily Traffic158 (2023)
Truck Traffic24%
Lanes On Bridge2

Inspection & Ownership

Last InspectionNovember 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number057002100.1023A

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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