NB Ia 58 over U.S. 20
GoodBlack Hawk County, Iowa · At the Jct. U.S. 20 · Structure no. 000000000605635
- Built
- 1984
- 41 years old
- Condition
- Good
- inspected February 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 272 ft
- 4 main spans
- Daily traffic
- 2,698
- 2022 count
- Owner
- State
- State Highway Agency
About this bridge
NB Ia 58 over U.S. 20 is a prestressed concrete stringer/multi-beam or girder carrying NB Ia 58 over U.S. 20 in Black Hawk County, Iowa. It was built in 1984, so it is 41 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 2,698 vehicles a day, roughly 8% of them trucks, projected to reach 2,698 by 2044. The structure is 272 ft (82.9 m) long and 46 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was NB Ia 58 over U.S. 20 built?
It was built in 1984, making it 41 years old in 2025.
What condition is NB Ia 58 over U.S. 20 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 February 2024.
How much traffic does NB Ia 58 over U.S. 20 carry?
About 2,698 vehicles per day (2022 count), of which roughly 8% are trucks.
How long is NB Ia 58 over U.S. 20?
The structure is 272 ft (82.9 m) long with a longest span of 96 ft (29.3 m) and a deck 46 ft wide.
Who owns NB Ia 58 over U.S. 20?
It is owned by the State Highway Agency.