485 Avenue over Burlington Northern RR
Grant County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 485 Avenue over Burlington Northern RR in Grant County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1978, making it 47 years old at the 2025 inventory.
- It carries about 397 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 67 of the 205 inventoried bridges in Grant County rated fair (32.7%); 38 (18.5%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: substructure 6 to 7.
- Its most recent inspection on record is dated September 2024, 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 → (45.27968, -96.49407)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 7 | Good condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 184 ft |
| Location | 1S & 1.5W Big Stone |
| NBI structure number | 000000026360032 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Grant County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr I029 over Indian Rv | 1976 | 6,600 | Fair |
| US012 over Whetstone Rv Div Channel | 1955 | 3,765 | Fair |
| Irr I029 S over 146 St | 1977 | 3,650 | Fair |
| Irr I029 N over 146 St | 1977 | 3,650 | Good |
| Irr I029 S over 149 St (fas 6266) | 1976 | 3,650 | Fair |
| Irr I029 N over 149 St (fas 6266) | 1976 | 3,650 | Fair |
All bridges nearby: Grant County, SD bridge conditions · every bridge in Grant County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.