US Bridges

325th ST over Rock Creek

FairPosted for load

Story County, Iowa · 082222707 · Structure no. 000000000008180

Built
1929
96 years old
Condition
Fair
inspected January 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
35 ft
1 main span
Daily traffic
190
2022 count
Owner
County
County Highway Agency

About this bridge

325th ST over Rock Creek is a steel stringer/multi-beam or girder carrying 325th ST over Rock Creek in Story County, Iowa. It was built in 1929, so it is 96 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. Its operating status is: posted for load restriction.

It carries about 190 vehicles a day, roughly 19% of them trucks, projected to reach 190 by 2043. The structure is 35 ft (10.7 m) long and 21 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries325th ST
CrossesRock Creek
Location082222707
RouteCounty Highway 0
CountyStory County
StateIowa
Coordinates41.88487, -93.39611
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating33 US tons
Inventory rating19 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length35 ft (10.7 m)
Longest span32 ft (9.8 m)
Deck width21 ft (6.5 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic190 (2022)
Projected traffic190 by 2043
Trucks19%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 325th ST over Rock Creek built?

It was built in 1929, making it 96 years old in 2025.

What condition is 325th ST over Rock 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 January 2023.

How much traffic does 325th ST over Rock Creek carry?

About 190 vehicles per day (2022 count), of which roughly 19% are trucks.

How long is 325th ST over Rock Creek?

The structure is 35 ft (10.7 m) long with a longest span of 32 ft (9.8 m) and a deck 21 ft wide.

Who owns 325th ST over Rock Creek?

It is owned by the County Highway Agency.