Rosslyn Station Access Improvements
The Rosslyn Metro Station is one of the busiest Metro Stations in Virginia. This project added three high speed elevators, an emergency access stairwell, a new mezzanine, an underground cross-connect passageway, extensive waterproofing, mechanical and ancillary spaces, and all new electrical and communications equipment to meet future ridership needs.
Atkinson performed the tunnel and shaft excavation under a subcontract to parent company Clark Construction, who completed the station structures and finishes scope of work. The underground work consisted of the excavation and support of a 38-foot by 43-foot by 116-foot deep shaft, a 42-foot diameter by 76-foot long modified-horseshoe mezzanine tunnel, and a 15-foot diameter by 25-foot long passageway tunnel. Atkinson constructed the project in an urban environment in the Rosslyn neighborhood of Arlington, VA, directly adjacent to a number of high-rise buildings, an active metro station, and existing tunnels. The new shaft and tunnels house three high-speed elevators to provide additional access to the existing Rosslyn Metro Station.
Atkinson excavated the shaft and mezzanine tunnel within the gneiss rock using controlled drill and blast excavation and excavated the passageway tunnel that tied into the existing metro station using mechanical excavation methods. The shaft ground support system consisted of long post-tensioned rock anchors and steel fiber-reinforced shotcrete. The mezzanine tunnel and passageway tunnel ground support system consisted of Swellex bolts—varying in length—and steel fiber-reinforced shotcrete.
Atkinson successfully completed the work without affecting the Washington Metropolitan Area Transit Authority (WMATA) operations at the existing station and with minimal noise disturbance to the surrounding community.