Ia 4 & 175 over Purgatory Creek

Fair

Calhoun County, Iowa · 2.8 Mi. S of N JCT Ia 175 · Structure no. 000000000016921

Built: 1973; 52 years old
Condition: Fair; inspected July 2024
Type: Slab; Concrete Continuous
Length: 133 ft; 3 main spans
Daily traffic: 1,410; 2022 count
Owner: State; State Highway Agency

About this bridge

Ia 4 & 175 over Purgatory Creek is a concrete continuous slab carrying Ia 4 & 175 over Purgatory Creek in Calhoun County, Iowa. It was built in 1973, so it is 52 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 1,410 vehicles a day, roughly 20% of them trucks, projected to reach 1,410 by 2044. The structure is 133 ft (40.5 m) long and 47 ft wide.

Location

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CarriesIa 4 & 175

CrossesPurgatory Creek

Location2.8 Mi. S of N JCT Ia 175

RouteState Highway 4

CountyCalhoun County

StateIowa

Coordinates42.26706, -94.59366

Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

Component	Rating	Meaning
Deck	6 Satisfactory	Structural elements show some minor deterioration.
Superstructure	7 Good	Some minor problems.
Substructure	6 Satisfactory	Structural elements show some minor deterioration.
Channel and channel protection	7 Good	Some minor problems.

Last inspectionJuly 2024

Inspection intervalevery 24 months

Operating statusOpen, no restriction

ScourFoundations stable; scour within limits of footing or piles

Structural evaluation6: Equal to present minimum criteria

Deck geometry8: Equal to present desirable criteria

Waterway adequacy8: Equal to present desirable criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating66 US tons

Inventory rating39.6 US tons

Structure

Structure typeSlab

MaterialConcrete Continuous

DeckConcrete, cast-in-place

Main spans3

Design loadHS 20

Structure length133 ft (40.5 m)

Longest span51 ft (15.5 m)

Deck width47 ft (14.4 m)

Roadway width44 ft (13.4 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,410 (2022)

Projected traffic1,410 by 2044

Trucks20%

Lanes on structure2

Traffic directionTwo-way traffic

CarriesHighway

CrossesWaterway

Detour if closed—

TollOn a free road

National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency

Maintained byState Highway Agency

Historic statusNot eligible for the National Register of Historic Places

Work proposedNone recorded

Estimated improvement cost—

NavigationNo navigation control on waterway

Frequently asked questions

When was Ia 4 & 175 over Purgatory Creek built?

It was built in 1973, making it 52 years old in 2025.

What condition is Ia 4 & 175 over Purgatory Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2024.

How much traffic does Ia 4 & 175 over Purgatory Creek carry?

About 1,410 vehicles per day (2022 count), of which roughly 20% are trucks.

How long is Ia 4 & 175 over Purgatory Creek?

The structure is 133 ft (40.5 m) long with a longest span of 51 ft (15.5 m) and a deck 47 ft wide.

Who owns Ia 4 & 175 over Purgatory Creek?

It is owned by the State Highway Agency.