US Bridges

US-31 NB over CSX RR

Fair

Mason County, Michigan · 3.1 MI E of Ludington · Structure no. 000000000006647

Built
1988
37 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
141 ft
3 main spans
Daily traffic
2,498
2007 count
Owner
State
State Highway Agency

About this bridge

US-31 NB over CSX RR is a prestressed concrete stringer/multi-beam or girder carrying US-31 NB over CSX RR in Mason County, Michigan. It was built in 1988, so it is 37 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 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 2,498 vehicles a day, roughly 15% of them trucks, projected to reach 3,385 by 2018. The structure is 141 ft (42.9 m) long and 66 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesUS-31 NB
CrossesCSX RR
Location3.1 MI E of Ludington
RouteU.S. Route 31
CountyMason County
StateMichigan
Coordinates43.95137, -86.38456
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89.6 US tons
Inventory rating53.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length141 ft (42.9 m)
Longest span47 ft (14.3 m)
Deck width66 ft (20.1 m)
Roadway width63 ft (19.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,498 (2007)
Projected traffic3,385 by 2018
Trucks15%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US-31 NB over CSX RR built?

It was built in 1988, making it 37 years old in 2025.

What condition is US-31 NB over CSX RR 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 2024.

How much traffic does US-31 NB over CSX RR carry?

About 2,498 vehicles per day (2007 count), of which roughly 15% are trucks.

How long is US-31 NB over CSX RR?

The structure is 141 ft (42.9 m) long with a longest span of 47 ft (14.3 m) and a deck 66 ft wide.

Who owns US-31 NB over CSX RR?

It is owned by the State Highway Agency.