US Bridges

NB Ia 27 over So Main ST

Good

Black Hawk County, Iowa · .3 MI S of University Ave · Structure no. 000000000601260

Built
1993
32 years old
Condition
Good
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
231 ft
3 main spans
Daily traffic
6,900
2022 count
Owner
State
State Highway Agency

About this bridge

NB Ia 27 over So Main ST is a steel continuous stringer/multi-beam or girder carrying NB Ia 27 over So Main ST in Black Hawk County, Iowa. It was built in 1993, so it is 32 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 6,900 vehicles a day, roughly 8% of them trucks, projected to reach 6,900 by 2042. The structure is 231 ft (70.4 m) long and 49 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNB Ia 27
CrossesSo Main ST
Location.3 MI S of University Ave
RouteState Highway 27
CountyBlack Hawk County
StateIowa
Coordinates42.50896, -92.44613
Functional classUrban Other Principal Arterial

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating83 US tons
Inventory rating48.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length231 ft (70.4 m)
Longest span99 ft (30.2 m)
Deck width49 ft (15 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,900 (2022)
Projected traffic6,900 by 2042
Trucks8%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was NB Ia 27 over So Main ST built?

It was built in 1993, making it 32 years old in 2025.

What condition is NB Ia 27 over So Main ST 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 NB Ia 27 over So Main ST carry?

About 6,900 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is NB Ia 27 over So Main ST?

The structure is 231 ft (70.4 m) long with a longest span of 99 ft (30.2 m) and a deck 49 ft wide.

Who owns NB Ia 27 over So Main ST?

It is owned by the State Highway Agency.