US Bridges

M-99 over Spring Brook

Fair

Jackson County, Michigan · 0.1 MI S of Eaton CO Line · Structure no. 000000000004382

Built
1999
26 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
55 ft
1 main span
Daily traffic
2,089
2007 count
Owner
State
State Highway Agency

About this bridge

M-99 over Spring Brook is a prestressed concrete stringer/multi-beam or girder carrying M-99 over Spring Brook in Jackson County, Michigan. It was built in 1999, so it is 26 years old, younger than the Michigan average of 48.3 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 2,089 vehicles a day, roughly 10% of them trucks, projected to reach 2,225 by 2018. The structure is 55 ft (16.8 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesM-99
CrossesSpring Brook
Location0.1 MI S of Eaton CO Line
RouteState Highway 99
CountyJackson County
StateMichigan
Coordinates42.42061, -84.64996
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating85.8 US tons
Inventory rating51.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length55 ft (16.8 m)
Longest span52 ft (15.8 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,089 (2007)
Projected traffic2,225 by 2018
Trucks10%
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

OwnerState Highway Agency
Maintained byState 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 M-99 over Spring Brook built?

It was built in 1999, making it 26 years old in 2025.

What condition is M-99 over Spring Brook 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 April 2023.

How much traffic does M-99 over Spring Brook carry?

About 2,089 vehicles per day (2007 count), of which roughly 10% are trucks.

How long is M-99 over Spring Brook?

The structure is 55 ft (16.8 m) long with a longest span of 52 ft (15.8 m) and a deck 47 ft wide.

Who owns M-99 over Spring Brook?

It is owned by the State Highway Agency.