FM
Carrying FM over BOONE RIVER
089253101, Hamilton, Iowa
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
FM in Hamilton, Iowa sits above 31% of rated Iowa bridges on inventory load rating (24 t), while its 1964 build year is earlier than 67% of Hamilton's recorded-year cohort (165 bridges).
FM in Hamilton, Iowa is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1964, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. The lowest applicable rating sets the federal condition category, so this Poor result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure IA:000000000172410
INTERSTATE-ERA · STEEL · MULTI-SPAN · DECK-LED · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- MULTI-SPAN 3 spans
- DECK-LED Deck-led
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-POOR Poor
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: FM
The FM bridge in Hamilton, Iowa carries FM over BOONE RIVER. It was built in 1964, making it 62 years old today. It was last reconstructed in 1986, extending its service life. The structure is built primarily of steel continuous and spans 3 sections, stretching 93.9 meters (308 feet) end to end. Daily traffic averages 499 vehicles, placing it in the lower-traffic tier of Iowa bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 5/9, substructure at 6/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules.
How FM compares
Age against the county: built in 1964, earlier than 110 of Hamilton's 165 bridges with a recorded construction year (67%), against a county median build year of 1972. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Iowa bridges with a recorded inventory load rating (23,718 of 23,719 rated).
FM vs every rated Iowa bridge
Inventory load rating (metric tons), FHWA NBI, this state
24 Top 69% higher than 31% of 23,718 bridges
rated Iowa bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Hamilton inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 165 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1964
- Last Reconstructed
- 1986
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 93.9 m (308 ft)
- Deck Width
- 9.8 m (32 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 499 vehicles/day
- Structure Number
- 000000000172410
Condition Analysis
- • The deck (driving surface) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • The superstructure (beams and supports above the deck) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • The substructure (piers and abutments) rates fair at 6/9, minor deterioration that routine maintenance should address.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
FM is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare FM against other structures in Hamilton and across Iowa. Iowa bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for FM?
FM in Hamilton, Iowa has a deck rating of 4/9, superstructure rating of 5/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is FM inspected?
FM's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 499 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. FM is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for FM?
FM has an NBI inventory load rating of 24.3 metric tons.
Who is responsible for maintaining FM?
FM is owned and maintained by County Highway Agency.
How old is FM and does age affect safety?
FM was built in 1964, making it 62 years old and last reconstructed in 1986.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.