E 11TH ST

over CEDAR RIVER

CITY BRIDGE NO. 6, Black Hawk County, Iowa

Condition

Poor

Year Built

1953

Daily Traffic

6,793

Length

62 ft

About This Bridge

E 11TH ST carries traffic over CEDAR RIVER in Black Hawk County, Iowa. Built in 1953, this structure is 73 years old, placing it among the older bridges still in active service. The bridge features steel continuous construction with a girder and floorbeam design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 6,793 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 62 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.

5

Deck Condition

Fair

4

Superstructure

Poor

5

Substructure

Fair

8

Channel & Protection

Very Good

4

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 superstructure rating of 4 shows advanced deterioration in beams or girders.

For a structure built in 1953, 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 girder and floorbeam 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

Year Built1953
Year Reconstructed1981
MaterialSteel Continuous
Design TypeGirder and Floorbeam
OwnerCity/Municipal

Dimensions

Total Length62 ft (18.8 m)
Max Span14 ft (4.1 m)
Deck Width7 ft
Deck Area3,694 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 3,694 sq ft determines surface maintenance scope.

Classification

Route TypeCity Street
Route Number0
Lanes On Bridge4
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.

6,793

Avg Daily Traffic (2022)

Vehicles per day crossing this bridge

Truck Traffic

Commercial vehicle percentage

6,793

Projected Future ADT

Estimated future demand

This bridge carries approximately 6,793 vehicles per day, translating to roughly 2,479,445 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Traffic projections estimate future volumes of 6,793 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

2.4 tons

Maximum allowable load for special permits

Inventory Rating

1.2 tons

Load level for normal traffic

The operating rating of 2.4 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 1.2 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

Status Changes

  • Entered poor condition in 2023
  • Became structurally deficient in 2023

Data: 2020-2024 FHWA National Bridge Inventory

Location

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43.277778, -93.761389

Identification

Structure Number000000000011830
NBI IDIA-000000000011830
State FIPS19
County FIPS013

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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.

E 11TH ST over CEDAR RIVER | Iowa