Mo State Highway J over Clarence Cannon Dam
Ralls County, Missouri · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Mo State Highway J over Clarence Cannon Dam in Ralls County, Missouri, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1983, making it 42 years old at the 2025 inventory.
- It carries about 1,573 vehicles a day (traffic count year 2020).
- It is one of 39 of the 136 inventoried bridges in Ralls County rated good (28.7%); 11 (8.1%) 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 August 2024, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (39.5242, -91.64361)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Steel girder and floorbeam |
| Length | about 364 ft |
| Location | Mark Twain Lake |
| NBI structure number | CEPLMSMO-000004 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | August 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Missouri department of transportation.
Busiest bridges in Ralls County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 61 S over Bear CR | 1990 | 10,100 | Good |
| US 61 S over NS RR | 1990 | 10,100 | Fair |
| US 61 N over NS RR | 1963 | 10,036 | Good |
| US 61 N over Bear CR | 1963 | 10,036 | Good |
| US 61 S over Salt Rvr | 1983 | 9,033 | Good |
| US 61 N over Salt River | 1963 | 8,731 | Fair |
All bridges nearby: Ralls County, MO bridge conditions · every bridge in Ralls County · Missouri bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.