L20 Loess Hills over Allen Creek
GoodHarrison County, Iowa · 079441104 · Structure no. 000000000027901
- Built
- 1990
- 35 years old
- Condition
- Good
- inspected January 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 151 ft
- 3 main spans
- Daily traffic
- 767
- 2022 count
- Owner
- County
- County Highway Agency
About this bridge
L20 Loess Hills over Allen Creek is a prestressed concrete stringer/multi-beam or girder carrying L20 Loess Hills over Allen Creek in Harrison County, Iowa. It was built in 1990, so it is 35 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 767 vehicles a day, roughly 8% of them trucks, projected to reach 767 by 2044. The structure is 151 ft (46 m) long and 39 ft wide. If it were closed, the detour would be 3.1 mi (5 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 | 8 Very Good | No problems noted. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was L20 Loess Hills over Allen Creek built?
It was built in 1990, making it 35 years old in 2025.
What condition is L20 Loess Hills over Allen 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 January 2024.
How much traffic does L20 Loess Hills over Allen Creek carry?
About 767 vehicles per day (2022 count), of which roughly 8% are trucks.
How long is L20 Loess Hills over Allen Creek?
The structure is 151 ft (46 m) long with a longest span of 69 ft (21 m) and a deck 39 ft wide.
Who owns L20 Loess Hills over Allen Creek?
It is owned by the County Highway Agency.