I-355 SB
Carrying I-355 SB over US 20
1.5 M S IL 19, DuPage, Illinois
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
I-355 SB in DuPage, Illinois sits above 21% of rated Illinois bridges on inventory load rating (31 t), while its 1970 build year is earlier than 71% of DuPage's recorded-year cohort (344 bridges).
I-355 SB in DuPage, Illinois is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1970, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. 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 IL:022011100000000
INTERSTATE-ERA · STEEL · MULTI-SPAN · SUPER-LED · HEAVY-ADT · STANDARD-LOAD · CAT-FAIR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- MULTI-SPAN 3 spans
- SUPER-LED Superstructure-led
- HEAVY-ADT Heavy ADT
- STANDARD-LOAD Standard 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: I-355 SB
The I-355 SB bridge in DuPage, Illinois carries I-355 SB over US 20. It was built in 1970, making it 56 years old today. It was last reconstructed in 1988, extending its service life. The structure is built primarily of steel continuous and spans 3 sections, stretching 56.9 meters (187 feet) end to end. Daily traffic averages 67,300 vehicles, placing it in the heavily-trafficked tier of Illinois bridges. It is owned and maintained by State 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 I-355 SB compares
Age against the county: built in 1970, earlier than 244 of DuPage's 344 bridges with a recorded construction year (71%), against a county median build year of 1988. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Illinois bridges with a recorded inventory load rating (26,904 of 26,928 rated).
I-355 SB vs every rated Illinois bridge
Inventory load rating (metric tons), FHWA NBI, this state
31 Top 79% higher than 21% of 26,904 bridges
rated Illinois 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.
DuPage inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 344 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
- 1970
- Last Reconstructed
- 1988
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 56.9 m (187 ft)
- Deck Width
- 18.5 m (61 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 67,300 vehicles/day
- Structure Number
- 022011100000000
Condition Analysis
- • The deck (driving surface) rates good at 7/9, with no significant deterioration on file.
- • At 6/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • 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 I-355 SB 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 I-355 SB against other structures in DuPage and across Illinois. Illinois 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 I-355 SB?
I-355 SB in DuPage, Illinois has a deck rating of 7/9, superstructure rating of 6/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is I-355 SB inspected?
I-355 SB'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 67,300 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. I-355 SB 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 I-355 SB?
I-355 SB has an NBI inventory load rating of 30.8 metric tons.
Who is responsible for maintaining I-355 SB?
I-355 SB is owned and maintained by State Highway Agency.
How old is I-355 SB and does age affect safety?
I-355 SB was built in 1970, making it 56 years old and last reconstructed in 1988.
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.