US Bridges

Linn-Benton RD over Trib to Knapp Creek

Fair

Linn County, Iowa · Benton-Linn Road · Structure no. 000000000220470

Built
1972
53 years old
Condition
Fair
inspected February 2023
Type
Culvert
Concrete Continuous
Length
21 ft
2 main spans
Daily traffic
1,530
2021 count
Owner
City
City or Municipal Highway Agency

About this bridge

Linn-Benton RD over Trib to Knapp Creek is a concrete continuous culvert carrying Linn-Benton RD over Trib to Knapp Creek in Linn County, Iowa. It was built in 1972, so it is 53 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 1,530 vehicles a day, roughly 2% of them trucks, projected to reach 1,530 by 2043. The structure is 21 ft (6.4 m) long and 30 ft wide.

Location

Open in Google Maps
CarriesLinn-Benton RD
CrossesTrib to Knapp Creek
LocationBenton-Linn Road
RouteCounty Highway 0
CountyLinn County
StateIowa
Coordinates41.87856, -91.83157
Functional classRural Minor Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.5 US tons
Inventory rating33.6 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadH 20
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width30 ft (9.1 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,530 (2021)
Projected traffic1,530 by 2043
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Linn-Benton RD over Trib to Knapp Creek built?

It was built in 1972, making it 53 years old in 2025.

What condition is Linn-Benton RD over Trib to Knapp 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 February 2023.

How much traffic does Linn-Benton RD over Trib to Knapp Creek carry?

About 1,530 vehicles per day (2021 count), of which roughly 2% are trucks.

How long is Linn-Benton RD over Trib to Knapp Creek?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m) and a deck 30 ft wide.

Who owns Linn-Benton RD over Trib to Knapp Creek?

It is owned by the City or Municipal Highway Agency.