US Bridges

SB Ia 1 over US 218

Fair

Johnson County, Iowa · At JCT U.S. 218 · Structure no. 000000000605545

Built
1983
42 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
268 ft
4 main spans
Daily traffic
7,650
2022 count
Owner
State
State Highway Agency

About this bridge

SB Ia 1 over US 218 is a prestressed concrete stringer/multi-beam or girder carrying SB Ia 1 over US 218 in Johnson County, Iowa. It was built in 1983, so it is 42 years old, younger 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 7,650 vehicles a day, roughly 6% of them trucks, projected to reach 7,650 by 2044. The structure is 268 ft (81.7 m) long and 43 ft wide.

Location

Open in Google Maps
CarriesSB Ia 1
CrossesUS 218
LocationAt JCT U.S. 218
RouteState Highway 1
CountyJohnson County
StateIowa
Coordinates41.63409, -91.56759
Functional classUrban Other Principal Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating65 US tons
Inventory rating37.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length268 ft (81.7 m)
Longest span92 ft (28 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,650 (2022)
Projected traffic7,650 by 2044
Trucks6%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was SB Ia 1 over US 218 built?

It was built in 1983, making it 42 years old in 2025.

What condition is SB Ia 1 over US 218 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 Ia 1 over US 218 carry?

About 7,650 vehicles per day (2022 count), of which roughly 6% are trucks.

How long is SB Ia 1 over US 218?

The structure is 268 ft (81.7 m) long with a longest span of 92 ft (28 m) and a deck 43 ft wide.

Who owns SB Ia 1 over US 218?

It is owned by the State Highway Agency.