Farragut North Station

As part of a critical infrastructure upgrade for WMATA (Washington Metropolitan Area Transit Authority), Freyssinet, Inc. led the structural strengthening of Beam 10 at Farragut North Station, one of the busiest stops on Washington D.C.’s Red Line. The project addressed severe deterioration in a 72-foot-long, 14-foot-wide, 7-foot-tall post-tensioned concrete beam located directly above active rail tracks. Due to the beam’s compromised condition and the station’s high traffic volume, the repair required a highly customized solution and meticulous planning.

Project Duration

August 2009-January 2012
Location

Washington, D.C.
Client

WMATA

Farragut North Station Repairs

Engineering-Led Repair Strategy

Freyssinet USA conducts repair work in Washington DC tunnel

Before construction began, Freyssinet was engaged to perform a detailed structural analysis using proprietary techniques, including SlotStress® testing. The investigation revealed that the beam’s post-tensioning cables were significantly damaged and no longer structurally sound. Freyssinet collaborated closely with WMATA to develop a tailored repair design and budget, ensuring alignment between technical requirements and operational constraints.

Freyssinet’s responsibilities included both engineering design and construction execution under extremely limited working hours (primarily during non-revenue service windows and single-tracking weekends).

Key Elements of the Project Included:

Post-Tensioning Replacement: Substituted damaged cables with new reinforcement to restore structural capacity.
Beam Encapsulation: Enclosed the existing beam in high-strength, self-compacting concrete to enhance durability and load-bearing performance.
Mockups and Testing: Conducted full-scale mockups to simulate site conditions, validate formwork design, and test concrete behavior under real constraints.
Advanced Repair Techniques:
- Crack injection
- Carbon fiber reinforcement
- Synchronized jacking of the beam to relieve stress, supported by a newly constructed concrete pier beneath the platform
Precision Construction: Used scanning devices to avoid damaging existing reinforcement during drilling and installation.
Logistics and Temporary Works: Designed and installed custom formwork and working platforms over live tracks. A temporary batching plant was set up inside the station to mix and pump concrete into overhead formwork.

Farragut_North_Station_Repairs

Results of the Farragut North Station Repairs

Despite the complexity of the site and the limited access windows, Freyssinet completed the Farragut North Station repairs on time and to specification. The project showcases Freyssinet’s ability to deliver technically demanding structural rehabilitation in active transit environments, while balancing safety, innovation, and operational continuity.

In recognition of the project’s excellence, Freyssinet received a Certificate of Excellence in Concrete Repair and Restoration in May 2011, presented by the National Capital Chapter of the American Concrete Institute as part of the 2011 Metropolitan D.C. Concrete Construction Awards.

Tunnel Solutions

Tunnels are long-term investments, often exceeding their intended lifespan. Harsh conditions, especially water infiltration, accelerate deterioration. Freyssinet provides expert solutions to restore integrity and extend service life through advanced waterproofing and reinforcement.

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Tunnel Solutions

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