Structure B-23-AU · Logan County, CO

SH 63 Ml over South Platte River

Carries SH 63 Ml over South Platte River, 2.7mi N Of Jct I76.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructure8/9 · Very Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT498 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 8/9Substructure 6/9 · sets the rating

498 ft end to end, longest span 100 ft: about 7 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.

Built198244 years old
Length498.4 ft151.9 m
Daily traffic2,000counted 2020
Last inspectedJuly 2023every 24 months

Location

StateColorado
CountyLogan
Location2.7mi N Of Jct I76
CarriesSH 63 Ml
CrossesSouth Platte River
Coordinates40.53894, -103.26707

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length498.4 ft (151.9 m)
Max Span99.7 ft (30.4 m)
Deck Width42.7 ft (13 m)
Deck Area1974.7 sq m
Main Spans5
Year Built1982

Traffic

Avg Daily Traffic2,000 (2020)
Truck Traffic9%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberB-23-AU

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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