Structure 231790 · Madison County, IA

FM over South River

Carries FM over South River, 074262604.

Overall conditionPoor

Set by its lowest-rated component: Deck at 3 of 9.

How ratings work
Decksets the rating3/9 · Serious
Superstructure4/9 · Poor
Substructure5/9 · Fair
Channelnot part of overall5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT153 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 3/9 · sets the ratingSuperstructure 4/9Substructure 5/9

153 ft end to end, longest span 58 ft: about 2 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.

Built193690 years old
Length152.9 ft46.6 m
Daily traffic349counted 2022
Last inspectedAugust 2023every 24 months

Location

StateIowa
CountyMadison
Location074262604
CarriesFM
CrossesSouth River
Coordinates41.17902, -93.82626

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length152.9 ft (46.6 m)
Max Span58.1 ft (17.7 m)
Deck Width21.3 ft (6.5 m)
Deck Area302.9 sq m
Main Spans3
Year Built1936

Traffic

Avg Daily Traffic349 (2022)
Truck Traffic8%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000231790

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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