US Bridges

I-88 EB over Rock River

Fair

Whiteside County, Illinois · 3 MI W Rock Falls · Structure no. 098007900000000

Built
1972
53 years old, rebuilt 2002
Condition
Fair
inspected March 2023
Type
Box Beam or Girders - Single or Spread
Steel Continuous
Length
1,200 ft
8 main spans
Daily traffic
6,850
2023 count
Owner
State
State Highway Agency

About this bridge

I-88 EB over Rock River is a steel continuous box beam or girders - single or spread carrying I-88 EB over Rock River in Whiteside County, Illinois. It was built in 1972 and reconstructed in 2002, so it is 53 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 6,850 vehicles a day, roughly 36% of them trucks, projected to reach 6,414 by 2046. The structure is 1,200 ft (365.8 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-88 EB
CrossesRock River
Location3 MI W Rock Falls
RouteInterstate 88
CountyWhiteside County
StateIllinois
Coordinates41.75646, -89.77335
Functional classRural Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating80.4 US tons
Inventory rating47.8 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadHS 20 + Mod
Structure length1,200 ft (365.8 m)
Longest span170 ft (51.8 m)
Deck width42 ft (12.8 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,850 (2023)
Projected traffic6,414 by 2046
Trucks36%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I-88 EB over Rock River built?

It was built in 1972, making it 53 years old in 2025. It was reconstructed in 2002.

What condition is I-88 EB over Rock River 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 March 2023.

How much traffic does I-88 EB over Rock River carry?

About 6,850 vehicles per day (2023 count), of which roughly 36% are trucks.

How long is I-88 EB over Rock River?

The structure is 1,200 ft (365.8 m) long with a longest span of 170 ft (51.8 m) and a deck 42 ft wide.

Who owns I-88 EB over Rock River?

It is owned by the State Highway Agency.