Structure BC-81-6.2-LT · Boulder County, CO

County Road 81 over Lefthand Creek

Carries County Road 81 over Lefthand Creek, 250 Ft N Of Lee Hill DR.

Overall conditionGood

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

How ratings work
Deck8/9 · Very Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT60 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 7/9 · sets the rating

60 ft end to end. 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 box-beam bridge.

Built20197 years old
Length59.7 ft18.2 m
Daily traffic735counted 2023
Last inspectedFebruary 2025every 24 months

Location

StateColorado
CountyBoulder
Location250 Ft N Of Lee Hill DR
CarriesCounty Road 81
CrossesLefthand Creek
Coordinates40.09336, -105.35117

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length59.7 ft (18.2 m)
Max Span53.5 ft (16.3 m)
Deck Width29.9 ft (9.1 m)
Deck Area165.6 sq m
Main Spans1
Year Built2019

Traffic

Avg Daily Traffic735 (2023)
Truck Traffic8%
Lanes On Bridge2

Inspection & Ownership

Last InspectionFebruary 2025
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberBC-81-6.2-LT

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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