US Bridges

EB US 20 over Maquoketa River

Fair

Delaware County, Iowa · 1.7 Mi. E of Jct. Ia 13 · Structure no. 000000000602015

Built
1974
51 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
356 ft
3 main spans
Daily traffic
3,850
2022 count
Owner
State
State Highway Agency

About this bridge

EB US 20 over Maquoketa River is a steel continuous stringer/multi-beam or girder carrying EB US 20 over Maquoketa River in Delaware 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 3,850 vehicles a day, roughly 31% of them trucks, projected to reach 3,850 by 2042. The structure is 356 ft (108.5 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesEB US 20
CrossesMaquoketa River
Location1.7 Mi. E of Jct. Ia 13
RouteU.S. Route 20
CountyDelaware County
StateIowa
Coordinates42.46989, -91.44943
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.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating56.8 US tons
Inventory rating34.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length356 ft (108.5 m)
Longest span137 ft (41.8 m)
Deck width44 ft (13.3 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,850 (2022)
Projected traffic3,850 by 2042
Trucks31%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was EB US 20 over Maquoketa River built?

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

What condition is EB US 20 over Maquoketa River 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 July 2023.

How much traffic does EB US 20 over Maquoketa River carry?

About 3,850 vehicles per day (2022 count), of which roughly 31% are trucks.

How long is EB US 20 over Maquoketa River?

The structure is 356 ft (108.5 m) long with a longest span of 137 ft (41.8 m) and a deck 44 ft wide.

Who owns EB US 20 over Maquoketa River?

It is owned by the State Highway Agency.