US Bridges

SB I-35 over Drainage Ditch #29

Fair

Wright County, Iowa · 1.3 MI N of SR C70 · Structure no. 000000000602600

Built
1974
51 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
151 ft
3 main spans
Daily traffic
8,250
2022 count
Owner
State
State Highway Agency

About this bridge

SB I-35 over Drainage Ditch #29 is a prestressed concrete stringer/multi-beam or girder carrying SB I-35 over Drainage Ditch #29 in Wright County, Iowa. It was built in 1974, so it is 51 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 8,250 vehicles a day, roughly 31% of them trucks, projected to reach 8,250 by 2044. The structure is 151 ft (46 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSB I-35
CrossesDrainage Ditch #29
Location1.3 MI N of SR C70
RouteInterstate 35
CountyWright County
StateIowa
Coordinates42.58783, -93.53098
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.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
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 geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.3 US tons
Inventory rating47.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length151 ft (46 m)
Longest span52 ft (15.9 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,250 (2022)
Projected traffic8,250 by 2044
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 SB I-35 over Drainage Ditch #29 built?

It was built in 1974, making it 51 years old in 2025.

What condition is SB I-35 over Drainage Ditch #29 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 January 2024.

How much traffic does SB I-35 over Drainage Ditch #29 carry?

About 8,250 vehicles per day (2022 count), of which roughly 31% are trucks.

How long is SB I-35 over Drainage Ditch #29?

The structure is 151 ft (46 m) long with a longest span of 52 ft (15.9 m) and a deck 43 ft wide.

Who owns SB I-35 over Drainage Ditch #29?

It is owned by the State Highway Agency.