Structure L25128001+09001 · Lewis and Clark County, MT
Carries Glass DR over Helena Valley Canal 150, 11m N Helena.
Set by its lowest-rated component: Deck and Superstructure at 6 of 9.
How ratings work22 ft end to end. 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 | Lewis and Clark |
| Location | 11m N Helena |
| Carries | Glass DR |
| Crosses | Helena Valley Canal 150 |
| Coordinates | 46.71720, -111.99972 |
| Material | Wood or Timber |
| Design | Stringer/Multi-beam |
| Total Length | 22.3 ft (6.8 m) |
| Max Span | 21.3 ft (6.5 m) |
| Deck Width | 26.6 ft (8.1 m) |
| Deck Area | 55.1 sq m |
| Main Spans | 1 |
| Year Built | 1958 |
| Avg Daily Traffic | 611 (2023) |
| Lanes On Bridge | 2 |
| Last Inspection | November 2024 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | L25128001+09001 |
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.