WB I-235
Carrying WB I-235 over 17TH ST
1.3 mi. W of Jct. IA 28, Polk, Iowa
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
WB I-235 in Polk, Iowa sits above 86% of rated Iowa bridges on inventory load rating (42 t), while its 1967 build year is earlier than 78% of Polk's recorded-year cohort (545 bridges).
WB I-235 in Polk, Iowa is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 1967, 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 IA:000000000042230
INTERSTATE-ERA · PRESTRESS · MULTI-SPAN · TIED-CTRL · HEAVY-ADT · HEAVY-LOAD · CAT-GOOD
- INTERSTATE-ERA 1950–1979
- PRESTRESS Prestressed concrete
- MULTI-SPAN 3 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- HEAVY-LOAD Heavy 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: WB I-235
The WB I-235 bridge in Polk, Iowa carries WB I-235 over 17TH ST. It was built in 1967, making it 59 years old today. It was last reconstructed in 2004, extending its service life. The structure is built primarily of prestressed concrete and spans 3 sections, stretching 44.2 meters (145 feet) end to end. Daily traffic averages 56,600 vehicles, placing it in the heavily-trafficked tier of Iowa 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. No reported major component scores in the Poor range under the current federal condition thresholds.
How WB I-235 compares
Age against the county: built in 1967, earlier than 424 of Polk's 545 bridges with a recorded construction year (78%), against a county median build year of 1994. 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).
WB I-235 vs every rated Iowa bridge
Inventory load rating (metric tons), FHWA NBI, this state
42 Top 14% higher than 86% 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.
Polk inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 545 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
- 1967
- Last Reconstructed
- 2004
- Material
- Prestressed Concrete
- Number of Spans
- 3
- Structure Length
- 44.2 m (145 ft)
- Deck Width
- 20.4 m (67 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 56,600 vehicles/day
- Structure Number
- 000000000042230
Condition Analysis
- • The deck (driving surface) rates good at 7/9, with no significant deterioration on file.
- • 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 WB I-235 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 WB I-235 against other structures in Polk 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 WB I-235?
WB I-235 in Polk, Iowa 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 WB I-235 inspected?
WB I-235'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 56,600 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. WB I-235 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 WB I-235?
WB I-235 has an NBI inventory load rating of 41.8 metric tons.
Who is responsible for maintaining WB I-235?
WB I-235 is owned and maintained by State Highway Agency.
How old is WB I-235 and does age affect safety?
WB I-235 was built in 1967, making it 59 years old and last reconstructed in 2004.
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.