Structure 204790 · Johnson County, IA
Carries FM 310th ST over Stream, 080052503.
Set by its lowest-rated component: Deck and Substructure at 5 of 9.
How ratings work20 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 | Iowa |
| County | Johnson |
| Location | 080052503 |
| Carries | FM 310th ST |
| Crosses | Stream |
| Coordinates | 41.70739, -91.37250 |
| Material | Wood or Timber |
| Design | Stringer/Multi-beam |
| Total Length | 20.0 ft (6.1 m) |
| Max Span | 20.0 ft (6.1 m) |
| Deck Width | 20.0 ft (6.1 m) |
| Deck Area | 37.2 sq m |
| Main Spans | 1 |
| Year Built | 1900 |
| Avg Daily Traffic | 60 (2021) |
| Lanes On Bridge | 2 |
| Last Inspection | April 2023 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is possibly eligible (requires evaluation) |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 000000000204790 |
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.