US Bridges

N 1st Ave over Rillito Creek

Fair

Pima County, Arizona · 1000 Ft S Bromley Ave · Structure no. 09617

Built
1961
64 years old
Condition
Fair
inspected July 2023
Type
Channel Beam
Prestressed Concrete
Length
363 ft
6 main spans
Daily traffic
26,020
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

N 1st Ave over Rillito Creek is a prestressed concrete channel beam carrying N 1st Ave over Rillito Creek in Pima County, Arizona. It was built in 1961, so it is 64 years old, older than the Arizona average of 47.8 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 26,020 vehicles a day, roughly 10% of them trucks, projected to reach 26,030 by 2042. The structure is 363 ft (110.6 m) long and 64 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesN 1st Ave
CrossesRillito Creek
Location1000 Ft S Bromley Ave
RouteCity Street 0
CountyPima County
StateArizona
Coordinates32.2886, -110.9611
Functional classUrban Minor 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 protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.9 US tons
Inventory rating27 US tons

Structure

Structure typeChannel Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length363 ft (110.6 m)
Longest span60 ft (18.3 m)
Deck width64 ft (19.5 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deck30 ft (9.1 m)

Traffic and service

Average daily traffic26,020 (2023)
Projected traffic26,030 by 2042
Trucks10%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
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 N 1st Ave over Rillito Creek built?

It was built in 1961, making it 64 years old in 2025.

What condition is N 1st Ave over Rillito 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 July 2023.

How much traffic does N 1st Ave over Rillito Creek carry?

About 26,020 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is N 1st Ave over Rillito Creek?

The structure is 363 ft (110.6 m) long with a longest span of 60 ft (18.3 m) and a deck 64 ft wide.

Who owns N 1st Ave over Rillito Creek?

It is owned by the City or Municipal Highway Agency.