US Bridges

Ia 48 over Nishna River Overflow

Good

Cass County, Iowa · 1.7 Mi. S. of Jct. US 6 · Structure no. 000000000017731

Built
1995
30 years old
Condition
Good
inspected February 2023
Type
Slab
Concrete Continuous
Length
133 ft
3 main spans
Daily traffic
1,120
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 48 over Nishna River Overflow is a concrete continuous slab carrying Ia 48 over Nishna River Overflow in Cass County, Iowa. It was built in 1995, so it is 30 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,120 vehicles a day, roughly 12% of them trucks, projected to reach 1,120 by 2042. The structure is 133 ft (40.5 m) long and 39 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesIa 48
CrossesNishna River Overflow
Location1.7 Mi. S. of Jct. US 6
RouteState Highway 48
CountyCass County
StateIowa
Coordinates41.29361, -95.13724
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating62.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length133 ft (40.5 m)
Longest span51 ft (15.5 m)
Deck width39 ft (11.9 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,120 (2022)
Projected traffic1,120 by 2042
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

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 Ia 48 over Nishna River Overflow built?

It was built in 1995, making it 30 years old in 2025.

What condition is Ia 48 over Nishna River Overflow in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2023.

How much traffic does Ia 48 over Nishna River Overflow carry?

About 1,120 vehicles per day (2022 count), of which roughly 12% are trucks.

How long is Ia 48 over Nishna River Overflow?

The structure is 133 ft (40.5 m) long with a longest span of 51 ft (15.5 m) and a deck 39 ft wide.

Who owns Ia 48 over Nishna River Overflow?

It is owned by the State Highway Agency.