SR C-20 over I-35
Franklin County, Iowa · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SR C-20 over I-35 in Franklin County, Iowa, 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 1973, making it 52 years old at the 2025 inventory.
- It carries about 15 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 103 of the 227 inventoried bridges in Franklin County rated good (45.4%); 28 (12.3%) 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 November 2024, on a 24-month routine inspection cycle.
- 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 → (42.86256, -93.35065)
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 | Prestressed concrete stringer or multi-beam girder |
| Length | about 278 ft |
| Location | 2.0 Miles South of SR C13 |
| NBI structure number | 000000000602480 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Franklin County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-35 over Drainage Ditch | 1972 | 17,300 | Good |
| I-35 over Drainage Ditch | 1973 | 17,000 | Good |
| I-35 over Drainage Ditch | 1972 | 16,900 | Fair |
| I-35 over Stream | 1974 | 15,300 | Fair |
| I-35 over Drainage Ditch NO.48 | 1974 | 15,100 | Good |
| NB I-35 over Buffalo Creek | 1973 | 8,600 | Good |
All bridges nearby: Franklin County, IA bridge conditions · every bridge in Franklin County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.