US-31 over Manistee River
Manistee County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US-31 over Manistee River in Manistee County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1933 and reconstructed in 2023, making it 92 years old at the 2025 inventory.
- It carries about 17,789 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 18 of the 35 inventoried bridges in Manistee County rated fair (51.4%); 5 (14.3%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- It was rated poor in the 2024 inventory and is now fair (deck 3 to 7, superstructure 5 to 6, substructure 5 to 6).
- Status change: reopened since 2024, when it was closed.
- Its most recent inspection on record is dated September 2024, on a 8-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (44.25016, -86.31875)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 3 | 7 | Good condition |
| Superstructure | 5 | 6 | Satisfactory condition |
| Substructure | 5 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel movable bascule |
| Length | about 315 ft |
| Location | In Manistee |
| NBI structure number | 000000000006436 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 8 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Manistee County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-115 over Betsie River | 1940 | 4,219 | Fair |
| M-55 over Pine Creek | 1932 | 4,202 | Fair |
| M-55 over Manistee River | 2021 | 3,408 | Good |
| M-55 over Pine River | 1934 | 3,175 | Fair |
| East Lake Road over Little Manistee River | 1964 | 3,000 | Fair |
| M-115 over Dutchman Creek | 1937 | 2,670 | Fair |
All bridges nearby: Manistee County, MI bridge conditions · every bridge in Manistee County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.