IRR BIA RTE 735
over SUKKWAN STRAIT
3.0 MILES EAST OF HYDABUR, Prince of Wales-Hyder Census Area, Alaska
Condition
PoorYear Built
1970
Daily Traffic
5
Length
50 ft
About This Bridge
IRR BIA RTE 735 carries traffic over SUKKWAN STRAIT in Prince of Wales-Hyder Census Area, Alaska. Built in 1970, this structure is 56 years old, placing it among the older bridges still in active service. The bridge features concrete construction with a box beam - multiple design, a combination chosen by engineers to meet the specific requirements of this crossing.
Approximately 5 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.
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 50 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.
Concrete bridges offer excellent durability and relatively low maintenance requirements. They resist corrosion well but can develop cracking over time, particularly in regions with freeze-thaw cycles or heavy use of deicing chemicals. Regular inspection focuses on detecting cracks, spalling, and reinforcement corrosion.
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.
Deck Condition
Poor
Superstructure
Poor
Substructure
Poor
Channel & Protection
Very Good
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 deck rating of 4 indicates advanced deterioration affecting the driving surface. The superstructure rating of 4 shows advanced deterioration in beams or girders. The substructure rating of 4 reflects significant wear in piers, abutments, or foundations.
For a structure built in 1970, the current condition reflects the cumulative effects of age, traffic, and environmental exposure. If this bridge were closed, traffic would face a detour of approximately 124 miles, underscoring the importance of maintaining this crossing.
Bridge Details
Concrete is the primary structural material, which influences maintenance requirements and expected lifespan. The box beam - multiple design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to Tribal.
Construction
Dimensions
Span dimensions affect structural design choices and load distribution. The deck area of 2,237 sq ft determines surface maintenance scope.
Classification
Status
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.
5
Avg Daily Traffic (2021)
Vehicles per day crossing this bridge
—
Truck Traffic
Commercial vehicle percentage
12
Projected Future ADT
Estimated future demand
This bridge carries approximately 5 vehicles per day, translating to roughly 1,825 crossings annually. Lower traffic volumes generally result in less structural wear over time.
Traffic projections estimate future volumes of 12 vehicles daily, a 140% 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
0.3 tons
Maximum allowable load for special permits
Inventory Rating
—
Load level for normal traffic
5-Year Condition Trend
↓DecliningCondition has declined by 1.0 rating points since 2020
Status Changes
- Entered poor condition in 2022
- Became structurally deficient in 2022
Data: 2020-2024 FHWA National Bridge Inventory
Location
Loading map...
55.371944, -133.710556
Identification
Explore More
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.