US Bridges

Werth Road over Lwr S Br Thunder Bay Riv

Fair

Alpena County, Michigan · 8 MI SW of Alpena · Structure no. 000000000000341

Built
1939
86 years old, rebuilt 1990
Condition
Fair
inspected August 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
120 ft
2 main spans
Daily traffic
1,850
2010 count
Owner
County
County Highway Agency

About this bridge

Werth Road over Lwr S Br Thunder Bay Riv is a prestressed concrete box beam or girders - multiple carrying Werth Road over Lwr S Br Thunder Bay Riv in Alpena County, Michigan. It was built in 1939 and reconstructed in 1990, so it is 86 years old, older 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 1,850 vehicles a day, projected to reach 2,400 by 2030. The structure is 120 ft (36.5 m) long and 31 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesWerth Road
CrossesLwr S Br Thunder Bay Riv
Location8 MI SW of Alpena
RouteCounty Highway 434
CountyAlpena County
StateMichigan
Coordinates44.98284, -83.56943
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating66 US tons
Inventory rating39.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans2
Design loadHS 20
Structure length120 ft (36.5 m)
Longest span58 ft (17.6 m)
Deck width31 ft (9.6 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,850 (2010)
Projected traffic2,400 by 2030
Trucks0%
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

OwnerCounty Highway Agency
Maintained byCounty 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 Werth Road over Lwr S Br Thunder Bay Riv built?

It was built in 1939, making it 86 years old in 2025. It was reconstructed in 1990.

What condition is Werth Road over Lwr S Br Thunder Bay Riv 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 Werth Road over Lwr S Br Thunder Bay Riv carry?

About 1,850 vehicles per day (2010 count).

How long is Werth Road over Lwr S Br Thunder Bay Riv?

The structure is 120 ft (36.5 m) long with a longest span of 58 ft (17.6 m) and a deck 31 ft wide.

Who owns Werth Road over Lwr S Br Thunder Bay Riv?

It is owned by the County Highway Agency.