US Bridges

Quinsippi Island R over Quincy Bay

Fair

Adams County, Illinois · SE SEC34 T15 R9W · Structure no. 001601300000000

Built
2013
12 years old
Condition
Fair
inspected August 2023
Type
Girder and Floorbeam System
Steel
Length
611 ft
6 main spans
Daily traffic
200
2024 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

Quinsippi Island R over Quincy Bay is a steel girder and floorbeam system carrying Quinsippi Island R over Quincy Bay in Adams County, Illinois. It was built in 2013, so it is 12 years old, younger 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 200 vehicles a day, roughly 2% of them trucks, projected to reach 202 by 2046. The structure is 611 ft (186.1 m) long and 20 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesQuinsippi Island R
CrossesQuincy Bay
LocationSE SEC34 T15 R9W
RouteCounty Highway 0
CountyAdams County
StateIllinois
Coordinates39.94714, -91.4181
Functional classUrban Local

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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating59.3 US tons
Inventory rating35.7 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckWood or timber
Main spans6 (+2 approach)
Design loadUnknown
Structure length611 ft (186.1 m)
Longest span95 ft (29 m)
Deck width20 ft (6 m)
Roadway width20 ft (6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic200 (2024)
Projected traffic202 by 2046
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township 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 Quinsippi Island R over Quincy Bay built?

It was built in 2013, making it 12 years old in 2025.

What condition is Quinsippi Island R over Quincy Bay 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 August 2023.

How much traffic does Quinsippi Island R over Quincy Bay carry?

About 200 vehicles per day (2024 count), of which roughly 2% are trucks.

How long is Quinsippi Island R over Quincy Bay?

The structure is 611 ft (186.1 m) long with a longest span of 95 ft (29 m) and a deck 20 ft wide.

Who owns Quinsippi Island R over Quincy Bay?

It is owned by the Town or Township Highway Agency.