Structure 9988 · St. Clair County, MI
Carries I-94 WB over ST Clair River Cn Rr, At Port Huron.
Set by its lowest-rated component: Deck and Substructure at 7 of 9.
How ratings work6,178 ft end to end, longest span 871 ft: about 17 football fields, or 1.2 miles. 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 through truss.
| State | Michigan |
| County | St. Clair |
| Location | At Port Huron |
| Carries | I-94 WB |
| Crosses | ST Clair River Cn Rr |
| Coordinates | 42.99929, -82.42487 |
| Material | Steel |
| Design | Truss - Thru |
| Total Length | 6178.5 ft (1883.2 m) |
| Max Span | 871.1 ft (265.5 m) |
| Deck Width | 37.4 ft (11.4 m) |
| Deck Area | 21468.5 sq m |
| Main Spans | 3 |
| Year Built | 1938 (reconstructed 1999) |
| Avg Daily Traffic | 7,234 (2007) |
| Truck Traffic | 28% |
| Lanes On Bridge | 3 |
| Lanes Under Bridge | 17 |
| Last Inspection | October 2024 |
| Inspection Frequency | Every 12 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is on the National Register of Historic Places |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 000000000009988 |
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.