US Bridges

NB I-29 over Keg Creek

Fair

Mills County, Iowa · 0.7 Mi. S of S Jct. US 34 · Structure no. 000000000036230

Built
1971
54 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
265 ft
3 main spans
Daily traffic
6,850
2022 count
Owner
State
State Highway Agency

About this bridge

NB I-29 over Keg Creek is a steel continuous stringer/multi-beam or girder carrying NB I-29 over Keg Creek in Mills County, Iowa. It was built in 1971, so it is 54 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 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 6,850 vehicles a day, roughly 31% of them trucks, projected to reach 6,850 by 2043. The structure is 265 ft (80.8 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNB I-29
CrossesKeg Creek
Location0.7 Mi. S of S Jct. US 34
RouteInterstate 29
CountyMills County
StateIowa
Coordinates40.99201, -95.80297
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length265 ft (80.8 m)
Longest span101 ft (30.8 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,850 (2022)
Projected traffic6,850 by 2043
Trucks31%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-29 over Keg Creek built?

It was built in 1971, making it 54 years old in 2025.

What condition is NB I-29 over Keg Creek 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 2023.

How much traffic does NB I-29 over Keg Creek carry?

About 6,850 vehicles per day (2022 count), of which roughly 31% are trucks.

How long is NB I-29 over Keg Creek?

The structure is 265 ft (80.8 m) long with a longest span of 101 ft (30.8 m) and a deck 43 ft wide.

Who owns NB I-29 over Keg Creek?

It is owned by the State Highway Agency.