M-46 over Pine River
Gratiot County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-46 over Pine River in Gratiot County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1930 and reconstructed in 1984, making it 95 years old at the 2025 inventory.
- It carries about 9,548 vehicles a day (traffic count year 2007).
- Its listed owner is the state highway agency.
- It is one of 81 of the 167 inventoried bridges in Gratiot County rated fair (48.5%); 22 (13.2%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated May 2023, on a 24-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- 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 → (43.40783, -84.61874)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 89 ft |
| Location | In St Louis |
| NBI structure number | 000000000003112 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Gratiot County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-127 NB over US-127 Br | 1961 | 15,400 | Fair |
| US-127 SB over US-127 Br | 1961 | 15,400 | Fair |
| M-46 & US-127BR over US-127 | 1961 | 11,219 | Poor |
| US-127 NB over Maple River | 1988 | 10,831 | Fair |
| US-127 SB over Maple River | 1955 | 10,831 | Good |
| US-127 Br over Pine River | 1928 | 10,432 | Fair |
All bridges nearby: Gratiot County, MI bridge conditions · every bridge in Gratiot County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.