US Bridges

Old Mamalahoa HWY over Unnamed Stream

FairPosted for load

Hawaii County, Hawaii · Tmk: 4-6-013:015 · Structure no. 001470001100003

Built
1924
101 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Concrete Continuous
Length
74 ft
3 main spans
Daily traffic
1,778
1999 count
Owner
County
County Highway Agency

About this bridge

Old Mamalahoa HWY over Unnamed Stream is a concrete continuous stringer/multi-beam or girder carrying Old Mamalahoa HWY over Unnamed Stream in Hawaii County, Hawaii. It was built in 1924, so it is 101 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 5 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 1,778 vehicles a day, roughly 1% of them trucks, projected to reach 4,166 by 2042. The structure is 74 ft (22.7 m) long and 18 ft wide. If it were closed, the detour would be 13 mi (21 km).

Location

Open in Google Maps
CarriesOld Mamalahoa HWY
CrossesUnnamed Stream
LocationTmk: 4-6-013:015
RouteCounty Highway 2450
CountyHawaii County
StateHawaii
Coordinates20.04668, -155.53826
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
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 alignment6: Equal to present minimum criteria
Operating rating25.7 US tons
Inventory rating14.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadUnknown
Structure length74 ft (22.7 m)
Longest span28 ft (8.5 m)
Deck width18 ft (5.6 m)
Roadway width13 ft (4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,778 (1999)
Projected traffic4,166 by 2042
Trucks1%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed13 mi (21 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$100,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Old Mamalahoa HWY over Unnamed Stream built?

It was built in 1924, making it 101 years old in 2025.

What condition is Old Mamalahoa HWY over Unnamed Stream 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 June 2024.

How much traffic does Old Mamalahoa HWY over Unnamed Stream carry?

About 1,778 vehicles per day (1999 count), of which roughly 1% are trucks.

How long is Old Mamalahoa HWY over Unnamed Stream?

The structure is 74 ft (22.7 m) long with a longest span of 28 ft (8.5 m) and a deck 18 ft wide.

Who owns Old Mamalahoa HWY over Unnamed Stream?

It is owned by the County Highway Agency.