Transit-Project of the Year

New York Avenue Infill Station
Washington, D.C.

A team of construction professionals successfully added the first new in-fill New York Avenue Metrorail station to the Washington Metropolitan Area Transit Authority's Red Line, while only briefly shutting down service.

"This design/build project is very cool," said one of the judges. "The team had to work between two operating centers. It's a great project."

SL, a joint venture of Slattery Skanska Inc. of Whitestone, N.Y. and the Lane Construction Corp. of Meriden, Conn., received the $84 million design-build contract for the station, a hiking and biking viaduct and tie-ins to the existing WMATA Red Line in June 2002. It was expected to finish on time in December.

The team had experience designing and building similar transit projects in the Northeast, but this was one of WMATA's first forays into design-build.

The undertaking represents the first new transit station in the United States constructed between two existing and operating transit stations. WMATA plans more in-fill stations.

The site, immediately adjacent to the Red Line and the Northeast Corridor rail line between Washington, D.C., and Boston, presented some significant challenges. The transit authority could not afford to have its line down or inconvenience riders.

SL recommended a simple and easily constructed station, using modular component techniques, prestressed and precast concrete, mechanically stabilized embankment retaining walls, composite deck and parapet prefabrication and casting techniques, box-culverts and offsite manufacture of major components.

The job resulted in a completely new station design that the transit authority will be able to adapt and replicate at other locations.

Rather than use WMATA's typical cast-in-place construction for the major service and equipment rooms at both the north and south ends of the station, the team used a precast concrete box-culvert technology. The rooms house automatic train control equipment and electrical, mechanical and HVAC systems and were located within 20 ft. of live track.

The box-culvert cells were fabricated offsite, trucked to the station during the day and erected in segments at night, during regular track outages.

More than 10,400 sq. ft. of mechanically stabilized embankment retaining walls support the service and equipment rooms and portions of the new station, as well as the south access to the adjacent Metropolitan Branch Trail, a viaduct and superstructure for future hiking and biking access. Placing the MSEs required no pile-supported foundations.

SL used a composite precast deck and parapet slab segments to construct the viaduct superstructure for the trail. One hundred twenty, 12.3-ton deck and parapet segments were manufactured offsite in 8-ft., 3-in. lengths, complete with electrical blockouts, anchorage angles, shear connector pockets and parapet wall structures. Crews erected and post-tensioned the segments.

To provide access to the trail, SL ordered a precast structural concrete stairway tower and solo elevator tower. Four precast structural concrete stairways connect the main terminal with the station platforms.

Rather than cast-in-place beams and girders for the station superstructure, SL employed a modified American Association of State Highway and Transportation Officials-style trapezoidal box section, prestressed concrete girders, beams and architectural arch-shape segments.

The system, similar to that used in highway bridge construction, reduced the number of foundations, pier columns, cross girders and related elements that were needed. In addition, the structural support elements could be manufactured offsite, with better quality controls, and staged for erection.

WMATA recently redefined the look of its station canopy structures, replacing concrete with a heavy structural-steel plate frame, metal roof and skylights. The New York Avenue station, the first with the new design, required 1.1 million lbs. of structural steel plate, 450 ft. long, spanning almost 45 ft. in width.

It arrived in nine segments ready for erection, which the team coordinated around the Red Line's operating hours. Again, offsite fabrication allowed for greater quality control and space and time savings at the site.

In addition to building the new station, SL relocated an 80-year-old B & O Railroad bridge so it could be used for a new inbound track way to the New York Avenue station. Trains began crossing the relocated bridge in September. WMATA expects about 6,600 people will use the station.

Owner: The Washington Metropolitan Area Transit Authority WMATA
Design-Build Contractor: "Sl, A Joint Venture of Slattery Skanska Inc.& The Lane Construction Corporation"
Engineering, Design, & Architectural: "Jacobs Sverdup Civil, Inc."
Ornamental & Architectural Metals: Accent Architectural
Automatic Train Control Systems: "Alstom Signaling, Inc."
Concrete Forming Systems: "Conesco DOKA, LTD"
Glass Curtain Walls, Storefronts, and Door Systems: "Custom Glass Services, Inc."
Track Work, Rail Systems, and Railroad Structures: "Delta Railroad Construction, Inc."
Mechanical, HVAC, & Plumbing: "John J Kirlin, Inc./Utley Mechanical JV"

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