US Bridges

I-8 EB over Gillespie Canal

Poor

Maricopa County, Arizona · 8.6 MI W JCT SR 85 · Structure no. 00489

Built
1957
68 years old
Condition
Poor
inspected February 2024
Type
Slab
Concrete Continuous
Length
43 ft
2 main spans
Daily traffic
6,978
2022 count
Owner
State
State Highway Agency

About this bridge

I-8 EB over Gillespie Canal is a concrete continuous slab carrying I-8 EB over Gillespie Canal in Maricopa County, Arizona. It was built in 1957, so it is 68 years old, older than the Arizona average of 47.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 6,978 vehicles a day, roughly 26% of them trucks, projected to reach 6,988 by 2042. The structure is 43 ft (13.1 m) long and 45 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-8 EB
CrossesGillespie Canal
Location8.6 MI W JCT SR 85
RouteInterstate 8
CountyMaricopa County
StateArizona
Coordinates32.9229, -112.8787
Functional classRural Principal Arterial - Interstate

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41 US tons
Inventory rating24 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length43 ft (13.1 m)
Longest span21 ft (6.4 m)
Deck width45 ft (13.7 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,978 (2022)
Projected traffic6,988 by 2042
Trucks26%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$1,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-8 EB over Gillespie Canal built?

It was built in 1957, making it 68 years old in 2025.

What condition is I-8 EB over Gillespie Canal in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in February 2024.

How much traffic does I-8 EB over Gillespie Canal carry?

About 6,978 vehicles per day (2022 count), of which roughly 26% are trucks.

How long is I-8 EB over Gillespie Canal?

The structure is 43 ft (13.1 m) long with a longest span of 21 ft (6.4 m) and a deck 45 ft wide.

Who owns I-8 EB over Gillespie Canal?

It is owned by the State Highway Agency.