Structure 43270 · Pottawattamie County, IA

US 6 over Silver Creek

Carries US 6 over Silver Creek, 1.0 Mi. E Of SR L66.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT245 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 7/9

245 ft end to end, longest span 93 ft: 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 multi-beam bridge.

Built196165 years old
Length245.1 ft74.7 m
Daily traffic2,820counted 2022
Last inspectedJune 2024every 24 months

Location

StateIowa
CountyPottawattamie
Location1.0 Mi. E Of SR L66
CarriesUS 6
CrossesSilver Creek
Coordinates41.28937, -95.51751

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length245.1 ft (74.7 m)
Max Span92.8 ft (28.3 m)
Deck Width36.1 ft (11 m)
Deck Area821.7 sq m
Main Spans3
Year Built1961

Traffic

Avg Daily Traffic2,820 (2022)
Truck Traffic15%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000043270

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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