HAWAII BELT RD

over NANUE STRM

1.66MI W/KAUNIHO RD, Hawaii County, Hawaii

Condition

Poor

Year Built

1952

Daily Traffic

6,700

Length

54 ft

About This Bridge

HAWAII BELT RD carries traffic over NANUE STRM in Hawaii County, Hawaii. Built in 1952, this structure is 74 years old, placing it among the older bridges still in active service. The bridge features steel construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 6,700 vehicles cross this bridge daily, indicating lower traffic volumes common for local roads and rural routes. While traffic is lighter, these bridges still serve essential community transportation needs. Commercial trucks account for 9% of all crossings. This proportion of commercial traffic is typical for this roadway classification and is factored into the bridge's design load ratings.

The bridge is currently rated in poor condition based on federal inspection criteria established by the Federal Highway Administration. It is classified as structurally deficient, meaning one or more components have received a rating of 4 or below on the 0-9 scale. This designation indicates significant deterioration that warrants attention, though the bridge remains safe for travel within its posted limits. Structurally deficient does not mean unsafe—rather, it signals that repairs or replacement should be prioritized in transportation planning. With a total length of 54 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.

Steel bridges provide high strength-to-weight ratios, making them suitable for longer spans. However, they require ongoing protection against corrosion through painting or weathering steel designs. Inspectors pay close attention to connection points, fatigue cracking, and coating condition.

Federal law requires that all highway bridges be inspected at least every 24 months by qualified inspectors following the National Bridge Inspection Standards (NBIS). Some bridges with known issues or unusual characteristics may be inspected more frequently. Inspection data is reported to the National Bridge Inventory, a database maintained by the Federal Highway Administration that tracks the condition of all public highway bridges in the United States. This bridge data is sourced from that federal database and reflects the most recent available inspection results.

Condition Ratings

Structurally Deficient

This bridge has one or more component ratings of 4 or below, indicating significant deterioration that requires attention. The bridge remains safe for travel but may have load restrictions.

7

Deck Condition

Good

5

Superstructure

Fair

3

Substructure

Serious

7

Channel & Protection

Good

3

Lowest Rating

Determines condition category

NBI condition ratings range from 0 (failed) to 9 (excellent). Ratings of 4 or below are considered poor. The overall condition category is determined by the lowest individual component rating.

The substructure rating of 3 reflects serious deterioration in supports.

For a structure built in 1952, the current condition reflects the cumulative effects of age, traffic, and environmental exposure.

Bridge Details

Steel is the primary structural material, which influences maintenance requirements and expected lifespan. The stringer/multi-beam or girder design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to State Highway Agency.

Construction

Year Built1952
MaterialSteel
Design TypeStringer/Multi-beam or Girder
OwnerState Highway Agency

Dimensions

Total Length54 ft (16.4 m)
Max Span7 ft (2.2 m)
Deck Width4 ft
Deck Area1,898 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 1,898 sq ft determines surface maintenance scope.

Classification

Route TypeUS Highway
Route Number19
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour Critical8
Detour Length1 mi (2 km)

Traffic Data

Traffic volume data helps engineers assess bridge wear patterns and plan maintenance schedules. Average Daily Traffic (ADT) counts are updated periodically and represent typical weekday usage.

6,700

Avg Daily Traffic (2019)

Vehicles per day crossing this bridge

9%

Truck Traffic

Commercial vehicle percentage

6,781

Projected Future ADT

Estimated future demand

This bridge carries approximately 6,700 vehicles per day, translating to roughly 2,445,500 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Commercial trucks comprise 9% of traffic. Heavy vehicles cause disproportionate wear—a single fully loaded truck can have the impact of thousands of passenger cars on bridge deck surfaces.

Traffic projections estimate future volumes of 6,781 vehicles daily, a 1% increase from current levels. These projections inform capacity planning and potential upgrade requirements.

Load Ratings

Load ratings determine what weight this bridge can safely support. These values are critical for routing heavy vehicles and issuing overweight permits.

Operating Rating

6.2 tons

Maximum allowable load for special permits

Inventory Rating

4.8 tons

Load level for normal traffic

The operating rating of 6.2 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 4.8 tons is the safe load limit for everyday traffic without restrictions. These relatively low ratings may result in posted weight limits or route restrictions for heavy vehicles.

5-Year Condition Trend

Declining

Condition has declined by 1.0 rating points since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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20.980556, -155.776389

Identification

Structure Number001000190308146
NBI IDHI-001000190308146
State FIPS15
County FIPS001

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Data Source: Federal Highway Administration (FHWA) National Bridge Inventory 2024

Bridge inspection data is typically updated every 24 months. Conditions may have changed since the last inspection.

“Structurally deficient” does not mean a bridge is unsafe or likely to collapse. It indicates that one or more key structural elements are in poor or worse condition. Bridges are inspected regularly and may have load restrictions in place.

This data is for informational purposes only and should not be used for route clearance or vehicle weight decisions.

HAWAII BELT RD over NANUE STRM, Hawaii — Bridge Condition | BridgeReport.org | BridgeReport.org