US Bridges

US77 over Missouri River

Fair

Dakota County, Nebraska · Ncl South Sioux City · Structure no. S077 18870

Built
1981
44 years old, rebuilt 1983
Condition
Fair
inspected August 2024
Type
Arch - Thru
Steel
Length
1,502 ft
1 main span
Daily traffic
32,065
2018 count
Owner
State
State Highway Agency

About this bridge

US77 over Missouri River is a steel arch - thru carrying US77 over Missouri River in Dakota County, Nebraska. It was built in 1981 and reconstructed in 1983, so it is 44 years old, younger than the Nebraska average of 47.1 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 32,065 vehicles a day, roughly 2% of them trucks, projected to reach 43,159 by 2038. The structure is 1,502 ft (457.8 m) long and 68 ft wide. If it were closed, the detour would be 62.1 mi (100 km).

Location

Open in Google Maps
CarriesUS77
CrossesMissouri River
LocationNcl South Sioux City
RouteU.S. Route 77
CountyDakota County
StateNebraska
Coordinates42.488, -96.4136
Functional classUrban Principal Arterial - Other Freeway or Expressway

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 protection7 GoodSome minor problems.
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 rating36.4 US tons
Inventory rating26.5 US tons

Structure

Structure typeArch - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+7 approach)
Design loadHS 20
Structure length1,502 ft (457.8 m)
Longest span425 ft (129.5 m)
Deck width68 ft (20.6 m)
Roadway width63 ft (19.2 m)
Vertical clearance over deck17 ft (5.2 m)

Traffic and service

Average daily traffic32,065 (2018)
Projected traffic43,159 by 2038
Trucks2%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed62.1 mi (100 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US77 over Missouri River built?

It was built in 1981, making it 44 years old in 2025. It was reconstructed in 1983.

What condition is US77 over Missouri 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 August 2024.

How much traffic does US77 over Missouri River carry?

About 32,065 vehicles per day (2018 count), of which roughly 2% are trucks.

How long is US77 over Missouri River?

The structure is 1,502 ft (457.8 m) long with a longest span of 425 ft (129.5 m) and a deck 68 ft wide.

Who owns US77 over Missouri River?

It is owned by the State Highway Agency.