8TH AVE
over CEDAR RIVER
083072803, Linn County, Iowa
Condition
PoorYear Built
1938
Daily Traffic
9,382
Length
66 ft
About This Bridge
8TH AVE carries traffic over CEDAR RIVER in Linn County, Iowa. Built in 1938, this structure is 88 years old, making it a historic structure that has served the community for generations. The bridge features steel continuous construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.
Approximately 9,382 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 66 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.
The construction materials used in this bridge were selected based on engineering requirements, cost considerations, and local conditions at the time of construction.
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
Fair
Channel & Protection
Satisfactory
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.
For a structure built in 1938, the current condition reflects the cumulative effects of age, traffic, and environmental exposure.
Bridge Details
Steel Continuous 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 City/Municipal.
Construction
Dimensions
Span dimensions affect structural design choices and load distribution. The deck area of 4,072 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.
9,382
Avg Daily Traffic (2022)
Vehicles per day crossing this bridge
—
Truck Traffic
Commercial vehicle percentage
9,382
Projected Future ADT
Estimated future demand
This bridge carries approximately 9,382 vehicles per day, translating to roughly 3,424,430 crossings annually. Lower traffic volumes generally result in less structural wear over time.
Traffic projections estimate future volumes of 9,382 vehicles daily, a decrease 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
4.4 tons
Maximum allowable load for special permits
Inventory Rating
3.1 tons
Load level for normal traffic
The operating rating of 4.4 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.1 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
↓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
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42.385556, -93.288889
Identification
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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.