|Location:||Largo, MD||Category:||Mass Transportation|
|Owner:||Washington Metropolitan Area Transit Authority (WMATA)||Completed:||2004|
|Architect:||Hayes, Seay, Mattern & Mattern, Inc. (HSMM)|
Largo Town Center/Morgan Boulevard Stations
Using the design/build project delivery method, the team designed and built two stations, a large parking structure and day care center nearly two years faster than any other single station using WMATA’s traditional design-bid-build method. The project included design and construction of two station facilities at Morgan Boulevard and Largo Town Center; a new-look station platform and mezzanine canopies; wider platforms (30 feet compared to the existing 28 feet on current platforms); escalator stair-pairs; elevators from the platform to the mezzanine; design and construction of kiss-and-ride and bus bays at both stations; a child care facility at the Morgan Boulevard Station; surface parking for 596 park-and-ride vehicles at Morgan Boulevard; and two parking structures at the Largo Station that can accommodate 2,100 vehicles.
One of the challenging site conditions faced during design of the station was the area’s very poor soil quality; the team responded to this obstacle by incorporating ground improvements into its design, and by value engineering the design of track slabs, thus reducing the needed thickness of the slabs. The team’s recommendations resulted in a considerable cost savings. The communications systems for both the Morgan Boulevard and Largo Town Center stations include integration and routing of CCTV, public address, radio, digital display signs, and telephone systems. The team also developed and managed the System Integration Plan at both stations. The two parking structures were constructed simultaneously on a fast-track schedule.
The Largo Station site was previously a parking lot for the old USAir Arena. Significant re-grading of the site was necessary to achieve the 17-foot offset required for the upper and lower station entrances. All of the new structures at this site required deep foundation systems. The track work and platforms were founded on six-foot drilled shafts. The two parking structures were placed on over 800 steel piles. In addition, the team had to contend with high groundwater conditions throughout construction.
The Morgan Station site was heavily wooded at the start of construction. The Station was located in a cut and required over 40,000 cubic yards of excavation, the installation of significant support of excavation at the interfaces with the adjacent contracts as well as placement of over 120,000 cubic yards of borrow fills to level the site for nearly 600 parking spaces. During construction of the station invert, a previously unidentified zone of extremely loose sand required the installation of over 100 displacement piles to provide the necessary support for safe operation of the trains.