310TH St over Drainage
Story County, Iowa · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 310TH St over Drainage in Story County, Iowa, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1951 and reconstructed in 1988, making it 74 years old at the 2025 inventory.
- It carries about 90 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 40 of the 302 inventoried bridges in Story County rated poor (13.2%); 40 (13.2%) 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 January 2023, on a 24-month routine inspection cycle.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (41.90651, -93.31527)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 4 | 4 | Poor condition |
Bridge details
| Structure | Timber stringer or multi-beam girder |
| Length | about 24 ft |
| Location | 082212001 |
| NBI structure number | 000000000313530 |
| Condition class | Poor |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Story County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-35 over Ballard Creek | 1964 | 48,300 | Fair |
| I-35 over Walnut Creek | 1964 | 48,300 | Fair |
| I 35 over South Skunk Rvr Overflow | 2017 | 48,300 | Good |
| I-35 over Drainage Ditch | 1967 | 28,300 | Good |
| US 69 over Ioway Creek | 1924 | 24,600 | Good |
| NB I-35 over Bike Path | 1964 | 24,150 | Fair |
All bridges nearby: Story County, IA bridge conditions · every bridge in Story County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.