Karper Harbor RD over Johns Creek

Good

Dubuque County, Iowa · 087010704 · Structure no. 000000000145911

Built: 2021; 4 years old
Condition: Good; inspected March 2023
Type: Slab; Concrete Continuous
Length: 103 ft; 3 main spans
Daily traffic: 90; 2021 count
Owner: County; County Highway Agency

About this bridge

Karper Harbor RD over Johns Creek is a concrete continuous slab carrying Karper Harbor RD over Johns Creek in Dubuque County, Iowa. It was built in 2021, so it is 4 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 90 vehicles a day, projected to reach 90 by 2043. The structure is 103 ft (31.4 m) long and 33 ft wide.

Location

Open in Google Maps

CarriesKarper Harbor RD

CrossesJohns Creek

Location087010704

RouteCounty Highway 0

CountyDubuque County

StateIowa

Coordinates42.35975, -91.00471

Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

Component	Rating	Meaning
Deck	8 Very Good	No problems noted.
Superstructure	8 Very Good	No problems noted.
Substructure	8 Very Good	No problems noted.
Channel and channel protection	8 Very Good	No problems noted.

Last inspectionMarch 2023

Inspection intervalevery 24 months

Operating statusOpen, no restriction

ScourFoundations on dry land well above flood water elevations

Structural evaluation8: Equal to present desirable criteria

Deck geometry7: Better than present minimum criteria

Waterway adequacy9: Superior to present desirable criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating57.1 US tons

Inventory rating44.3 US tons

Structure

Structure typeSlab

MaterialConcrete Continuous

DeckConcrete, cast-in-place

Main spans3

Design loadHL 93

Structure length103 ft (31.4 m)

Longest span39 ft (11.9 m)

Deck width33 ft (10.1 m)

Roadway width30 ft (9.1 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic90 (2021)

Projected traffic90 by 2043

Trucks0%

Lanes on structure2

Traffic directionTwo-way traffic

CarriesHighway

CrossesWaterway

Detour if closed—

TollOn a free road

National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency

Maintained byCounty 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 Karper Harbor RD over Johns Creek built?

It was built in 2021, making it 4 years old in 2025.

What condition is Karper Harbor RD over Johns Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in March 2023.

How much traffic does Karper Harbor RD over Johns Creek carry?

About 90 vehicles per day (2021 count).

How long is Karper Harbor RD over Johns Creek?

The structure is 103 ft (31.4 m) long with a longest span of 39 ft (11.9 m) and a deck 33 ft wide.

Who owns Karper Harbor RD over Johns Creek?

It is owned by the County Highway Agency.