South Capitol St.

over Anacostia River

South Capitol St., District of Columbia, District of Columbia

Condition

Good

Year Built

2021

Daily Traffic

59,600

Length

145 ft

About This Bridge

South Capitol St. carries traffic over Anacostia River in District of Columbia, District of Columbia. Built in 2021, this structure is 5 years old, representing modern engineering and construction standards. The bridge features steel construction with a arch - deck design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 59,600 vehicles cross this bridge daily, making it a high-traffic corridor critical to regional transportation. Bridges carrying this volume require enhanced inspection schedules and proactive maintenance programs. Commercial trucks account for 5% 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 good condition based on federal inspection criteria established by the Federal Highway Administration. The structure meets current safety standards for its designated use and load capacity. With a total length of 145 feet, this structure falls within the typical range requiring standard inspection procedures conducted by certified bridge inspectors.

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

8

Deck Condition

Very Good

8

Superstructure

Very Good

8

Substructure

Very Good

8

Channel & Protection

Very Good

8

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.

With a lowest rating of 8, this bridge demonstrates very good condition with only minor issues.

For a structure built in 2021, maintaining good condition demonstrates effective maintenance practices.

Bridge Details

Steel is the primary structural material, which influences maintenance requirements and expected lifespan. The arch - deck 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 Built2021
MaterialSteel
Design TypeArch - Deck
OwnerState Highway Agency

Dimensions

Total Length145 ft (44.0 m)
Max Span54 ft (16.5 m)
Deck Width12 ft
Deck Area16,427 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 16,427 sq ft determines surface maintenance scope.

Classification

Route TypeCity Street
Route Number_
Lanes On Bridge6
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour CriticalNo
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.

59,600

Avg Daily Traffic (2020)

Vehicles per day crossing this bridge

5%

Truck Traffic

Commercial vehicle percentage

62,500

Projected Future ADT

Estimated future demand

This bridge carries approximately 59,600 vehicles per day, translating to roughly 21,754,000 crossings annually. This high volume places significant demands on the structure and necessitates frequent inspections.

Commercial trucks comprise 5% 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 62,500 vehicles daily, a 5% 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

4.8 tons

Maximum allowable load for special permits

Inventory Rating

3.7 tons

Load level for normal traffic

The operating rating of 4.8 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.7 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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39.151111, -77.797500

Identification

Structure Number1450
NBI IDDC-1450
State FIPS11
County FIPS001

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.

South Capitol St. over Anacostia River | District of Columbia