US Bridges

National City RD over Augres River

FairPosted for load

Iosco County, Michigan · 0.50 MI S of Keystone · Structure no. 000000000004144

Built
1978
47 years old
Condition
Fair
inspected June 2024
Type
Slab
Wood or Timber
Length
78 ft
3 main spans
Daily traffic
530
2006 count
Owner
County
County Highway Agency

About this bridge

National City RD over Augres River is a wood or timber slab carrying National City RD over Augres River in Iosco County, Michigan. It was built in 1978, so it is 47 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. Its operating status is: posted for load restriction.

It carries about 530 vehicles a day, roughly 10% of them trucks, projected to reach 950 by 2026. The structure is 78 ft (23.7 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesNational City RD
CrossesAugres River
Location0.50 MI S of Keystone
RouteCounty Highway 3527
CountyIosco County
StateMichigan
Coordinates44.17024, -83.72234
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating33.2 US tons
Inventory rating23.3 US tons

Structure

Structure typeSlab
MaterialWood or Timber
DeckWood or timber
Main spans3
Design loadH 20
Structure length78 ft (23.7 m)
Longest span26 ft (7.9 m)
Deck width30 ft (9.1 m)
Roadway width29 ft (8.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic530 (2006)
Projected traffic950 by 2026
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 National City RD over Augres River built?

It was built in 1978, making it 47 years old in 2025.

What condition is National City RD over Augres River 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 June 2024.

How much traffic does National City RD over Augres River carry?

About 530 vehicles per day (2006 count), of which roughly 10% are trucks.

How long is National City RD over Augres River?

The structure is 78 ft (23.7 m) long with a longest span of 26 ft (7.9 m) and a deck 30 ft wide.

Who owns National City RD over Augres River?

It is owned by the County Highway Agency.