Structure 287410 · Pottawattamie County, IA

450th Street over Stream

Carries 450th Street over Stream, 076390304.

Overall conditionFair

Set by its lowest-rated component: Deck and Substructure at 5 of 9.

How ratings work
Decksets the rating5/9 · Fair
Superstructure7/9 · Good
Substructuresets the rating5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
24 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 5/9 · sets the rating

24 ft end to end. Lengths are drawn to scale; at this length a semi-truck would be a speck. 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.

Built1940rebuilt 1987
Length24.0 ft7.3 m
Daily traffic11counted 2022
Last inspectedApril 2024every 24 months

Location

StateIowa
CountyPottawattamie
Location076390304
Carries450th Street
CrossesStream
Coordinates41.40910, -95.32769

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length24.0 ft (7.3 m)
Max Span23.0 ft (7 m)
Deck Width20.0 ft (6.1 m)
Deck Area44.5 sq m
Main Spans1
Year Built1940 (reconstructed 1987)

Traffic

Avg Daily Traffic11 (2022)
Lanes On Bridge2

Inspection & Ownership

Last InspectionApril 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000287410

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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