US Bridges

Old Mamalahoa HWY over Mamalahoa/Ahualoa #2

FairPosted for load

Hawaii County, Hawaii · Tmk: 4-6-007:025 · Structure no. 001460001100002

Built
1923
102 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Concrete
Length
25 ft
1 main span
Daily traffic
800
1981 count
Owner
County
County Highway Agency

About this bridge

Old Mamalahoa HWY over Mamalahoa/Ahualoa #2 is a concrete stringer/multi-beam or girder carrying Old Mamalahoa HWY over Mamalahoa/Ahualoa #2 in Hawaii County, Hawaii. It was built in 1923, so it is 102 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. Its operating status is: posted for load restriction.

It carries about 800 vehicles a day, projected to reach 1,000 by 2025. The structure is 25 ft (7.6 m) long and 20 ft wide. If it were closed, the detour would be 16.8 mi (27 km).

Location

Open in Google Maps
CarriesOld Mamalahoa HWY
CrossesMamalahoa/Ahualoa #2
LocationTmk: 4-6-007:025
RouteCounty Highway 0
CountyHawaii County
StateHawaii
Coordinates20.06194, -155.49306
Functional classRural Local

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating21.1 US tons
Inventory rating14.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length25 ft (7.6 m)
Longest span21 ft (6.5 m)
Deck width20 ft (6.1 m)
Roadway width18 ft (5.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic800 (1981)
Projected traffic1,000 by 2025
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesRelief for waterway
Detour if closed16.8 mi (27 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$180,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Old Mamalahoa HWY over Mamalahoa/Ahualoa #2 built?

It was built in 1923, making it 102 years old in 2025.

What condition is Old Mamalahoa HWY over Mamalahoa/Ahualoa #2 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 September 2024.

How much traffic does Old Mamalahoa HWY over Mamalahoa/Ahualoa #2 carry?

About 800 vehicles per day (1981 count).

How long is Old Mamalahoa HWY over Mamalahoa/Ahualoa #2?

The structure is 25 ft (7.6 m) long with a longest span of 21 ft (6.5 m) and a deck 20 ft wide.

Who owns Old Mamalahoa HWY over Mamalahoa/Ahualoa #2?

It is owned by the County Highway Agency.