FM 315TH St over Lime Creek
Delaware County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- FM 315TH St over Lime Creek in Delaware County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1978, making it 47 years old at the 2025 inventory.
- It carries about 530 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 160 of the 294 inventoried bridges in Delaware County rated fair (54.4%); 20 (6.8%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated March 2023, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (42.33689, -91.34049)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 128 ft |
| Location | 087042008 |
| NBI structure number | 000000000139621 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | March 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Delaware County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 20 over Stream | 1963 | 9,700 | Fair |
| US 20 over Stream | 1963 | 9,000 | Good |
| US 20 over Drainage Ditch | 1963 | 9,000 | Fair |
| Ia 13 over Maquoketa River | 1991 | 7,900 | Good |
| Ia 13 over US 20 | 1970 | 6,400 | Fair |
| W Marion St over Maquoketa River | 1980 | 6,294 | Poor |
All bridges nearby: Delaware County, IA bridge conditions · every bridge in Delaware County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.