Structure 6635 · Mason County, MI
Carries Old Us-31 over Durham Creek, 0.9 Mi N Of Oceana Col.
Set by its lowest-rated component: Deck and Superstructure and Substructure at 5 of 9.
How ratings work24 ft end to end, longest span 12 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 slab bridge.
| State | Michigan |
| County | Mason |
| Location | 0.9 Mi N Of Oceana Col |
| Carries | Old Us-31 |
| Crosses | Durham Creek |
| Coordinates | 43.83184, -86.39880 |
| Material | Concrete |
| Design | Slab |
| Total Length | 24.0 ft (7.3 m) |
| Max Span | 11.8 ft (3.6 m) |
| Deck Width | 45.3 ft (13.8 m) |
| Deck Area | 100.7 sq m |
| Main Spans | 2 |
| Year Built | 1925 |
| Avg Daily Traffic | 8,600 (1997) |
| Truck Traffic | 6% |
| Lanes On Bridge | 2 |
| Last Inspection | August 2024 |
| Inspection Frequency | Every 12 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 5 — Stable for scour |
| Structure Number | 000000000006635 |
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.