Irr Bia Rte 6 over Porcupine Creek
Sioux County, North Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr Bia Rte 6 over Porcupine Creek in Sioux County, North Dakota, 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 1969, making it 56 years old at the 2025 inventory.
- It carries about 173 vehicles a day (traffic count year 2023).
- It is one of 9 of the 22 inventoried bridges in Sioux County rated fair (40.9%); 1 (4.5%) 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 May 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 → (46.20431, -101.02403)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Concrete channel beam |
| Length | about 94 ft |
| Location | 6.8 Km West of Nd Hwy 6 |
| NBI structure number | 00000000000A046 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 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 North Dakota department of transportation.
Busiest bridges in Sioux County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irrsr Nd Hiway 24 over Beaver Holes Creek | 1965 | 1,830 | Fair |
| Irrsr Nd Hiway 24 over Porcupine Creek | 1963 | 1,740 | Fair |
| Irrsr Nd Hiway 24 over Battle Creek | 1965 | 1,700 | Fair |
| Irr Bia Rte 3 over Four Mile Creek Bridge | 2010 | 1,000 | Good |
| Irrsr Nd Hiway 24 over Four Mile Creek | 1930 | 750 | Fair |
| Irr Bia Rte 29 over One Mile Creek | 1950 | 401 | Poor |
All bridges nearby: Sioux County, ND bridge conditions · every bridge in Sioux County · North Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.