US Bridges

SR 77; NB & SB over Rillito Creek

Fair

Pima County, Arizona · 19.3 MI S JCT SR 79 · Structure no. 01550

Built
1970
55 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
316 ft
5 main spans
Daily traffic
31,053
2023 count
Owner
State
State Highway Agency

About this bridge

SR 77; NB & SB over Rillito Creek is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 77; NB & SB over Rillito Creek in Pima County, Arizona. It was built in 1970, so it is 55 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 31,053 vehicles a day, roughly 9% of them trucks, projected to reach 31,063 by 2042. The structure is 316 ft (96.3 m) long and 103 ft wide. If it were closed, the detour would be 34.8 mi (56 km).

Location

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CarriesSR 77; NB & SB
CrossesRillito Creek
Location19.3 MI S JCT SR 79
RouteState Highway 77
CountyPima County
StateArizona
Coordinates32.2938, -110.9783
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 protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length316 ft (96.3 m)
Longest span63 ft (19.2 m)
Deck width103 ft (31.3 m)
Roadway width92 ft (28 m)
Vertical clearance over deck30 ft (9.1 m)

Traffic and service

Average daily traffic31,053 (2023)
Projected traffic31,063 by 2042
Trucks9%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed34.8 mi (56 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 SR 77; NB & SB over Rillito Creek built?

It was built in 1970, making it 55 years old in 2025.

What condition is SR 77; NB & SB 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 January 2024.

How much traffic does SR 77; NB & SB over Rillito Creek carry?

About 31,053 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 77; NB & SB over Rillito Creek?

The structure is 316 ft (96.3 m) long with a longest span of 63 ft (19.2 m) and a deck 103 ft wide.

Who owns SR 77; NB & SB over Rillito Creek?

It is owned by the State Highway Agency.