IH USH 51-IH 39 NB
Carrying IH USH 51-IH 39 NB over JOHNSON CREEK
1.6M N JCT CTH DB TO E, Marathon, Wisconsin
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
IH USH 51-IH 39 NB in Marathon, Wisconsin sits above 24% of rated Wisconsin bridges on inventory load rating (29 t), while its 1972 build year is earlier than 66% of Marathon's recorded-year cohort (530 bridges).
IH USH 51-IH 39 NB in Marathon, Wisconsin is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 1972, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 7. The lowest applicable rating sets the federal condition category, so this Good 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 WI:B37014200000000
INTERSTATE-ERA · PRESTRESS · MULTI-SPAN · TIED-CTRL · HEAVY-ADT · STANDARD-LOAD · CAT-GOOD
- INTERSTATE-ERA 1950–1979
- PRESTRESS Prestressed concrete
- MULTI-SPAN 2 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- STANDARD-LOAD Standard load
- CAT-GOOD Good
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: IH USH 51-IH 39 NB
The IH USH 51-IH 39 NB bridge in Marathon, Wisconsin carries IH USH 51-IH 39 NB over JOHNSON CREEK. It was built in 1972, making it 54 years old today. It was last reconstructed in 2010, extending its service life. The structure is built primarily of prestressed concrete continuous and spans 2 sections, stretching 39.8 meters (131 feet) end to end. Daily traffic averages 21,200 vehicles, placing it in the heavily-trafficked tier of Wisconsin bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in good condition. All reported major components score above the Poor range.
How IH USH 51-IH 39 NB compares
Age against the county: built in 1972, earlier than 348 of Marathon's 530 bridges with a recorded construction year (66%), against a county median build year of 1985. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Wisconsin bridges with a recorded inventory load rating (14,446 rated).
IH USH 51-IH 39 NB vs every rated Wisconsin bridge
Inventory load rating (metric tons), FHWA NBI, this state
29 Top 76% higher than 24% of 14,446 bridges
rated Wisconsin 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.
Marathon inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 530 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
- 1972
- Last Reconstructed
- 2010
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 2
- Structure Length
- 39.8 m (131 ft)
- Deck Width
- 13.2 m (43 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 21,200 vehicles/day
- Structure Number
- B37014200000000
Condition Analysis
- • At 7/9, the deck (driving surface) is in good shape and shows no significant wear.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
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 IH USH 51-IH 39 NB 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 IH USH 51-IH 39 NB against other structures in Marathon and across Wisconsin. Wisconsin 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 IH USH 51-IH 39 NB?
IH USH 51-IH 39 NB in Marathon, Wisconsin has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is IH USH 51-IH 39 NB inspected?
IH USH 51-IH 39 NB'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 21,200 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IH USH 51-IH 39 NB is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for IH USH 51-IH 39 NB?
IH USH 51-IH 39 NB has an NBI inventory load rating of 29.2 metric tons.
Who is responsible for maintaining IH USH 51-IH 39 NB?
IH USH 51-IH 39 NB is owned and maintained by State Highway Agency.
How old is IH USH 51-IH 39 NB and does age affect safety?
IH USH 51-IH 39 NB was built in 1972, making it 54 years old and last reconstructed in 2010.
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.