US Bridges

US 20 over Miss. River HWY & RR

Fair

Dubuque County, Iowa · In Dubuque · Structure no. 000000000023880

Built
1943
82 years old, rebuilt 1992
Condition
Fair
inspected October 2021
Type
Arch - Thru
Steel Continuous
Length
5,760 ft
3 main spans
Daily traffic
17,700
2022 count
Owner
State
State Highway Agency

About this bridge

US 20 over Miss. River HWY & RR is a steel continuous arch - thru carrying US 20 over Miss. River HWY & RR in Dubuque County, Iowa. It was built in 1943 and reconstructed in 1992, so it is 82 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 17,700 vehicles a day, roughly 7% of them trucks, projected to reach 17,700 by 2041. The structure is 5,760 ft (1,755.6 m) long and 31 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesUS 20
CrossesMiss. River HWY & RR
LocationIn Dubuque
RouteU.S. Route 20
CountyDubuque County
StateIowa
Coordinates42.49178, -90.66252
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2021
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating53 US tons
Inventory rating37 US tons

Structure

Structure typeArch - Thru
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+36 approach)
Design loadHS 20
Structure length5,760 ft (1,755.6 m)
Longest span845 ft (257.6 m)
Deck width31 ft (9.3 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deck18 ft (5.5 m)

Traffic and service

Average daily traffic17,700 (2022)
Projected traffic17,700 by 2041
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway, waterway and railroad
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 20 over Miss. River HWY & RR built?

It was built in 1943, making it 82 years old in 2025. It was reconstructed in 1992.

What condition is US 20 over Miss. River HWY & RR 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 October 2021.

How much traffic does US 20 over Miss. River HWY & RR carry?

About 17,700 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is US 20 over Miss. River HWY & RR?

The structure is 5,760 ft (1,755.6 m) long with a longest span of 845 ft (257.6 m) and a deck 31 ft wide.

Who owns US 20 over Miss. River HWY & RR?

It is owned by the State Highway Agency.