US Bridges

D68 390th ST over Boone Creek

Good

Calhoun County, Iowa · 086333301 · Structure no. 000000000090611

Built
2020
5 years old
Condition
Good
inspected July 2023
Type
Slab
Concrete Continuous
Length
83 ft
3 main spans
Daily traffic
30
2022 count
Owner
County
County Highway Agency

About this bridge

D68 390th ST over Boone Creek is a concrete continuous slab carrying D68 390th ST over Boone Creek in Calhoun County, Iowa. It was built in 2020, so it is 5 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 30 vehicles a day, projected to reach 30 by 2043. The structure is 83 ft (25.3 m) long and 33 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesD68 390th ST
CrossesBoone Creek
Location086333301
RouteCounty Highway 0
CountyCalhoun County
StateIowa
Coordinates42.22395, -94.68954
Functional classRural Minor Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length83 ft (25.3 m)
Longest span31 ft (9.4 m)
Deck width33 ft (10.1 m)
Roadway width31 ft (9.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2022)
Projected traffic30 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$30,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was D68 390th ST over Boone Creek built?

It was built in 2020, making it 5 years old in 2025.

What condition is D68 390th ST over Boone 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 July 2023.

How much traffic does D68 390th ST over Boone Creek carry?

About 30 vehicles per day (2022 count).

How long is D68 390th ST over Boone Creek?

The structure is 83 ft (25.3 m) long with a longest span of 31 ft (9.4 m) and a deck 33 ft wide.

Who owns D68 390th ST over Boone Creek?

It is owned by the County Highway Agency.