US Bridges

NB US 59 over Boyer River

Fair

Crawford County, Iowa · 0.1 Mi. S of Ia 39 · Structure no. 000000000021490

Built
1967
58 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
291 ft
3 main spans
Daily traffic
4,400
2023 count
Owner
State
State Highway Agency

About this bridge

NB US 59 over Boyer River is a steel continuous stringer/multi-beam or girder carrying NB US 59 over Boyer River in Crawford County, Iowa. It was built in 1967, so it is 58 years old, older than the Iowa average of 45.5 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 4,400 vehicles a day, roughly 15% of them trucks, projected to reach 4,400 by 2043. The structure is 291 ft (88.7 m) long and 35 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNB US 59
CrossesBoyer River
Location0.1 Mi. S of Ia 39
RouteU.S. Route 59
CountyCrawford County
StateIowa
Coordinates42.01934, -95.36705
Functional classUrban Other Principal 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating61.7 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length291 ft (88.7 m)
Longest span112 ft (34.1 m)
Deck width35 ft (10.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,400 (2023)
Projected traffic4,400 by 2043
Trucks15%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was NB US 59 over Boyer River built?

It was built in 1967, making it 58 years old in 2025.

What condition is NB US 59 over Boyer 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 July 2023.

How much traffic does NB US 59 over Boyer River carry?

About 4,400 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is NB US 59 over Boyer River?

The structure is 291 ft (88.7 m) long with a longest span of 112 ft (34.1 m) and a deck 35 ft wide.

Who owns NB US 59 over Boyer River?

It is owned by the State Highway Agency.