Structure LRB12-1748BTC · Larimer County, CO

Mountain Shadow LN over Big Thompson River

Carries Mountain Shadow LN over Big Thompson River, 25 Ft S Of US HWY 34.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructuresets the rating8/9 · Very Good
Substructuresets the rating8/9 · Very Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT50 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

50 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 tee-beam bridge.

Built197749 years old
Length49.9 ft15.2 m
Daily traffic5counted 2023
Last inspectedJune 2023every 24 months

Location

StateColorado
CountyLarimer
Location25 Ft S Of US HWY 34
CarriesMountain Shadow LN
CrossesBig Thompson River
Coordinates40.42089, -105.35664

Physical Characteristics

MaterialPrestressed Concrete
DesignTee Beam
Total Length49.9 ft (15.2 m)
Max Span47.9 ft (14.6 m)
Deck Width12.1 ft (3.7 m)
Deck Area56.2 sq m
Main Spans1
Year Built1977

Traffic

Avg Daily Traffic5 (2023)
Lanes On Bridge1

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberLRB12-1748BTC

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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