US Bridges

US 20 and Ill 84 over Smallpox Creek

Fair

Jo Daviess County, Illinois · 3.8 MI SE of Galena · Structure no. 043003500000000

Built
1971
54 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
212 ft
3 main spans
Daily traffic
5,750
2021 count
Owner
State
State Highway Agency

About this bridge

US 20 and Ill 84 over Smallpox Creek is a prestressed concrete continuous stringer/multi-beam or girder carrying US 20 and Ill 84 over Smallpox Creek in Jo Daviess County, Illinois. It was built in 1971, so it is 54 years old, older than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 5,750 vehicles a day, roughly 16% of them trucks, projected to reach 5,808 by 2046. The structure is 212 ft (64.7 m) long and 34 ft wide. If it were closed, the detour would be 60.3 mi (97 km).

Location

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CarriesUS 20 and Ill 84
CrossesSmallpox Creek
Location3.8 MI SE of Galena
RouteU.S. Route 20
CountyJo Daviess County
StateIllinois
Coordinates42.38392, -90.37274
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating63.6 US tons
Inventory rating38.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length212 ft (64.7 m)
Longest span69 ft (21 m)
Deck width34 ft (10.4 m)
Roadway width31 ft (9.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,750 (2021)
Projected traffic5,808 by 2046
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed60.3 mi (97 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20 and Ill 84 over Smallpox Creek built?

It was built in 1971, making it 54 years old in 2025.

What condition is US 20 and Ill 84 over Smallpox Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2024.

How much traffic does US 20 and Ill 84 over Smallpox Creek carry?

About 5,750 vehicles per day (2021 count), of which roughly 16% are trucks.

How long is US 20 and Ill 84 over Smallpox Creek?

The structure is 212 ft (64.7 m) long with a longest span of 69 ft (21 m) and a deck 34 ft wide.

Who owns US 20 and Ill 84 over Smallpox Creek?

It is owned by the State Highway Agency.