US Bridges

Ill 177 over Silver CR Overflow E

Poor

St. Clair County, Illinois · 2.3MI W Il 4 · Structure no. 082006200000000

Built
1961
64 years old
Condition
Poor
inspected July 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
168 ft
4 main spans
Daily traffic
7,000
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 177 over Silver CR Overflow E is a steel continuous stringer/multi-beam or girder carrying Ill 177 over Silver CR Overflow E in St. Clair County, Illinois. It was built in 1961, so it is 64 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 2 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. Its operating status is: open, would be posted or closed except for temporary shoring.

It carries about 7,000 vehicles a day, roughly 5% of them trucks, projected to reach 5,858 by 2046. The structure is 168 ft (51.2 m) long and 36 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

CarriesIll 177
CrossesSilver CR Overflow E
Location2.3MI W Il 4
RouteState Highway 177
Coordinates38.49888, -89.83362
Functional classUrban Minor Arterial

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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure2 CriticalAdvanced deterioration of primary structural elements. Bridge may be closed until corrective action is taken.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 12 months
Operating statusOpen, would be posted or closed except for temporary shoring
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.7 US tons
Inventory rating36.8 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length168 ft (51.2 m)
Longest span41 ft (12.5 m)
Deck width36 ft (10.9 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,000 (2023)
Projected traffic5,858 by 2046
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$463,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Ill 177 over Silver CR Overflow E built?

It was built in 1961, making it 64 years old in 2025.

What condition is Ill 177 over Silver CR Overflow E 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 July 2024.

How much traffic does Ill 177 over Silver CR Overflow E carry?

About 7,000 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Ill 177 over Silver CR Overflow E?

The structure is 168 ft (51.2 m) long with a longest span of 41 ft (12.5 m) and a deck 36 ft wide.

Who owns Ill 177 over Silver CR Overflow E?

It is owned by the State Highway Agency.