Structure 184950 · Humboldt County, IA

FM over Dm River

Carries FM over Dm River, 092302305.

Overall conditionPoor

Set by its lowest-rated component: Superstructure and Substructure at 3 of 9.

How ratings work
Deck5/9 · Fair
Superstructuresets the rating3/9 · Serious
Substructuresets the rating3/9 · Serious
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT217 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9Superstructure 3/9 · sets the ratingSubstructure 3/9 · sets the rating

217 ft end to end: about 3 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 through truss.

Built1905rebuilt 1982
Length216.9 ft66.1 m
Daily traffic30counted 2022
Last inspectedNovember 2024every 12 months

Location

StateIowa
CountyHumboldt
Location092302305
CarriesFM
CrossesDm River
Coordinates42.77178, -94.35496

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length216.9 ft (66.1 m)
Max Span140.1 ft (42.7 m)
Deck Width15.7 ft (4.8 m)
Deck Area317.3 sq m
Main Spans1
Year Built1905 (reconstructed 1982)

Traffic

Avg Daily Traffic30 (2022)
Lanes On Bridge1

Inspection & Ownership

Last InspectionNovember 2024
Inspection FrequencyEvery 12 months
OwnerCounty Highway Agency
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour Critical8 — Stable, low risk
Structure Number000000000184950

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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