US Bridges

Mill ST over Black Branch

Fair

Sangamon County, Illinois · Mill ST in Rochester · Structure no. 084601300000000

Built
1930
95 years old
Condition
Fair
inspected March 2023
Type
Culvert
Concrete Continuous
Length
23 ft
2 main spans
Daily traffic
75
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

Mill ST over Black Branch is a concrete continuous culvert carrying Mill ST over Black Branch in Sangamon County, Illinois. It was built in 1930, so it is 95 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 6 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 75 vehicles a day, projected to reach 76 by 2046. The structure is 23 ft (7 m) long and 22 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesMill ST
CrossesBlack Branch
LocationMill ST in Rochester
RouteCity Street 0
CountySangamon County
StateIllinois
Coordinates39.75068, -89.53321
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating41.8 US tons
Inventory rating25 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length23 ft (7 m)
Longest span10 ft (3 m)
Deck width22 ft (6.6 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic75 (2022)
Projected traffic76 by 2046
Trucks0%
Lanes on structure2
Traffic directionTwo-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 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 Mill ST over Black Branch built?

It was built in 1930, making it 95 years old in 2025.

What condition is Mill ST over Black Branch 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 Mill ST over Black Branch carry?

About 75 vehicles per day (2022 count).

How long is Mill ST over Black Branch?

The structure is 23 ft (7 m) long with a longest span of 10 ft (3 m) and a deck 22 ft wide.

Who owns Mill ST over Black Branch?

It is owned by the City or Municipal Highway Agency.