FM RD M56
Carrying FM RD M56 over LONG BRANCH CREEK
80337, Shelby, Iowa
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
FM RD M56 in Shelby, Iowa sits above 18% of rated Iowa bridges on inventory load rating (19 t), while its 1958 build year is earlier than 73% of Shelby's recorded-year cohort (207 bridges).
FM RD M56 in Shelby, Iowa is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1958, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 5. The lowest applicable rating sets the federal condition category, so this Fair 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:000000000305950
INTERSTATE-ERA · PRESTRESS · MULTI-SPAN · DECK-LED · LOCAL-ADT · LIGHT-LOAD · CAT-FAIR
- INTERSTATE-ERA 1950–1979
- PRESTRESS Prestressed concrete
- MULTI-SPAN 3 spans
- DECK-LED Deck-led
- LOCAL-ADT Local ADT
- LIGHT-LOAD Light load
- CAT-FAIR Fair
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Structural health score
A composite of the deck, superstructure, and substructure NBI condition ratings plus the inventory load rating, benchmarked against the full national bridge corpus, distinct from the Good/Fair/Poor category above.
Bridge Snapshot: FM RD M56
The FM RD M56 bridge in Shelby, Iowa carries FM RD M56 over LONG BRANCH CREEK. It was built in 1958, making it 68 years old today. The structure is built primarily of prestressed concrete continuous and spans 3 sections, stretching 36.6 meters (120 feet) end to end. Daily traffic averages 50 vehicles, placing it in the lower-traffic tier of Iowa bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection places the weakest component in fair condition (see the full component ratings below). All reported major components score above the Poor range.
How FM RD M56 compares
Age against the county: built in 1958, earlier than 151 of Shelby's 207 bridges with a recorded construction year (73%), against a county median build year of 1978. 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 RD M56 vs every rated Iowa bridge
Inventory load rating (metric tons), FHWA NBI, this state
19 Top 82% higher than 18% 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.
Shelby inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 207 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
- 1958
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 3
- Structure Length
- 36.6 m (120 ft)
- Deck Width
- 6.9 m (23 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 50 vehicles/day
- Structure Number
- 000000000305950
Condition Analysis
- • At 5/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, 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
This page shows what the last federal inspection recorded, not whether FM RD M56 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare FM RD M56 against other structures in Shelby 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 RD M56?
FM RD M56 in Shelby, Iowa has a deck rating of 5/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is FM RD M56 inspected?
FM RD M56'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 50 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. FM RD M56 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for FM RD M56?
FM RD M56 has an NBI inventory load rating of 18.8 metric tons.
Who is responsible for maintaining FM RD M56?
FM RD M56 is owned and maintained by County Highway Agency.
How old is FM RD M56 and does age affect safety?
FM RD M56 was built in 1958, making it 68 years old.
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.