Structure 15MAS001 · Baker County, OR
Carries Black Mountain RD over Mason Dam Spillway, Mason Dam.
22 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 | Oregon |
| County | Baker |
| Location | Mason Dam |
| Carries | Black Mountain RD |
| Crosses | Mason Dam Spillway |
| Coordinates | 44.67289, -118.00013 |
| Material | Steel |
| Design | Stringer/Multi-beam |
| Total Length | 22.3 ft (6.8 m) |
| Max Span | 20.0 ft (6.1 m) |
| Deck Width | 26.9 ft (8.2 m) |
| Deck Area | 55.8 sq m |
| Main Spans | 1 |
| Year Built | 1968 |
| Avg Daily Traffic | 50 (2023) |
| Lanes On Bridge | 2 |
| Last Inspection | April 2023 |
| Inspection Frequency | Every 24 months |
| Owner | Bureau of Reclamation |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 15MAS001 |
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.