Structure 61520-00035 · Petroleum County, MT
Carries Road 317 over Alkali Creek, Sect 1 T18n R29e.
24 ft end to end, longest span 11 ft. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.
| State | Montana |
| County | Petroleum |
| Location | Sect 1 T18n R29e |
| Carries | Road 317 |
| Crosses | Alkali Creek |
| Coordinates | 47.35667, -107.96250 |
| Material | Wood or Timber |
| Design | Stringer/Multi-beam |
| Total Length | 24.0 ft (7.3 m) |
| Max Span | 11.2 ft (3.4 m) |
| Deck Width | 12.1 ft (3.7 m) |
| Deck Area | 27.0 sq m |
| Main Spans | 2 |
| Year Built | 1963 |
| Avg Daily Traffic | 2 (2024) |
| Lanes On Bridge | 1 |
| Last Inspection | August 2024 |
| Inspection Frequency | Every 24 months |
| Owner | Code 63 |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 5 — Stable for scour |
| Structure Number | 000061520-00035 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.