US Bridges

Wainaku ST over Wailuku River

Fair

Hawaii County, Hawaii · Tmk: 2-6-007:001 · Structure no. 001230001100002

Built
1919
106 years old
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
129 ft
2 main spans
Daily traffic
4,000
1986 count
Owner
County
County Highway Agency

About this bridge

Wainaku ST over Wailuku River is a concrete continuous box beam or girders - multiple carrying Wainaku ST over Wailuku River in Hawaii County, Hawaii. It was built in 1919, so it is 106 years old, older than the Hawaii average of 63.8 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 4,000 vehicles a day, projected to reach 5,000 by 2025. The structure is 129 ft (39.3 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesWainaku ST
CrossesWailuku River
LocationTmk: 2-6-007:001
CountyHawaii County
StateHawaii
Coordinates19.72618, -155.09045
Functional classUrban Collector

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2024
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 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 rating81.5 US tons
Inventory rating58.2 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length129 ft (39.3 m)
Longest span63 ft (19.2 m)
Deck width41 ft (12.6 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,000 (1986)
Projected traffic5,000 by 2025
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRelief for waterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$524,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Wainaku ST over Wailuku River built?

It was built in 1919, making it 106 years old in 2025.

What condition is Wainaku ST over Wailuku 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 January 2024.

How much traffic does Wainaku ST over Wailuku River carry?

About 4,000 vehicles per day (1986 count).

How long is Wainaku ST over Wailuku River?

The structure is 129 ft (39.3 m) long with a longest span of 63 ft (19.2 m) and a deck 41 ft wide.

Who owns Wainaku ST over Wailuku River?

It is owned by the County Highway Agency.