US Bridges

N Clark ST over Main Br Chicago Riv

Poor

Cook County, Illinois · 307 N Clark · Structure no. 016601000000000

Built
1929
96 years old, rebuilt 1985
Condition
Poor
inspected September 2024
Type
Movable - Bascule
Steel
Length
349 ft
1 main span
Daily traffic
6,800
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

N Clark ST over Main Br Chicago Riv is a steel movable - bascule carrying N Clark ST over Main Br Chicago Riv in Cook County, Illinois. It was built in 1929 and reconstructed in 1985, so it is 96 years old, older than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 6,800 vehicles a day, roughly 8% of them trucks, projected to reach 15,453 by 2046. The structure is 349 ft (106.4 m) long and 72 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesN Clark ST
CrossesMain Br Chicago Riv
Location307 N Clark
Coordinates41.88793, -87.63102
Functional classUrban Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating63.2 US tons
Inventory rating40 US tons

Structure

Structure typeMovable - Bascule
MaterialSteel
DeckOpen grating
Main spans1 (+4 approach)
Design loadHS 20
Structure length349 ft (106.4 m)
Longest span245 ft (74.8 m)
Deck width72 ft (21.9 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,800 (2022)
Projected traffic15,453 by 2046
Trucks8%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$2.1 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was N Clark ST over Main Br Chicago Riv built?

It was built in 1929, making it 96 years old in 2025. It was reconstructed in 1985.

What condition is N Clark ST over Main Br Chicago Riv in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in September 2024.

How much traffic does N Clark ST over Main Br Chicago Riv carry?

About 6,800 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is N Clark ST over Main Br Chicago Riv?

The structure is 349 ft (106.4 m) long with a longest span of 245 ft (74.8 m) and a deck 72 ft wide.

Who owns N Clark ST over Main Br Chicago Riv?

It is owned by the City or Municipal Highway Agency.