Structure 15240 · Cassia County, ID
Carries SH 77 over Marsh Creek, Near Declo Ncl.
Set by its lowest-rated component: Deck and Superstructure and Substructure at 6 of 9.
How ratings work24 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 rigid-frame bridge.
| State | Idaho |
| County | Cassia |
| Location | Near Declo Ncl |
| Carries | SH 77 |
| Crosses | Marsh Creek |
| Coordinates | 42.52092, -113.62814 |
| Material | Concrete |
| Design | Frame |
| Total Length | 24.0 ft (7.3 m) |
| Max Span | 24.0 ft (7.3 m) |
| Deck Width | 60.0 ft (18.3 m) |
| Deck Area | 133.6 sq m |
| Main Spans | 1 |
| Year Built | 1960 |
| Avg Daily Traffic | 4,900 (2023) |
| Truck Traffic | 3% |
| Lanes On Bridge | 2 |
| Last Inspection | March 2021 |
| Inspection Frequency | Every 48 months |
| Owner | State Highway Agency |
| Historical Significance | Historical significance is not determined |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 000000000015240 |
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.