US Bridges

I-75 SB over Saginaw R M-13 Gtwrr

Fair

Saginaw County, Michigan · At Zilwaukee · Structure no. 000000000009169

Built
1984
41 years old
Condition
Fair
inspected August 2024
Type
Segmental Box Girder
Prestressed Concrete Continuous
Length
8,085 ft
26 main spans
Daily traffic
23,450
2007 count
Owner
State
State Highway Agency

About this bridge

I-75 SB over Saginaw R M-13 Gtwrr is a prestressed concrete continuous segmental box girder carrying I-75 SB over Saginaw R M-13 Gtwrr in Saginaw County, Michigan. It was built in 1984, so it is 41 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 23,450 vehicles a day, roughly 7% of them trucks, projected to reach 34,201 by 2018. The structure is 8,085 ft (2,464.3 m) long and 74 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesI-75 SB
CrossesSaginaw R M-13 Gtwrr
LocationAt Zilwaukee
RouteInterstate 75
CountySaginaw County
StateMichigan
Coordinates43.47854, -83.90644
Functional classUrban Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.6 US tons
Inventory rating12.9 US tons

Structure

Structure typeSegmental Box Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans26
Design loadHS 25 or greater
Structure length8,085 ft (2,464.3 m)
Longest span392 ft (119.5 m)
Deck width74 ft (22.7 m)
Roadway width72 ft (22 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic23,450 (2007)
Projected traffic34,201 by 2018
Trucks7%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway, waterway and railroad
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I-75 SB over Saginaw R M-13 Gtwrr built?

It was built in 1984, making it 41 years old in 2025.

What condition is I-75 SB over Saginaw R M-13 Gtwrr 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 August 2024.

How much traffic does I-75 SB over Saginaw R M-13 Gtwrr carry?

About 23,450 vehicles per day (2007 count), of which roughly 7% are trucks.

How long is I-75 SB over Saginaw R M-13 Gtwrr?

The structure is 8,085 ft (2,464.3 m) long with a longest span of 392 ft (119.5 m) and a deck 74 ft wide.

Who owns I-75 SB over Saginaw R M-13 Gtwrr?

It is owned by the State Highway Agency.