Complicated Geometry Frames a D.C. Building
The $162.5-million Square 54, a mixed-use project in the heart of Washington, D.C.'s Foggy Bottom neighborhood, was wrapped up within budget and one month ahead of schedule last February. The project involved building a five-level, below-grade parking deck for 1,062 cars; a 10-story commercial office building with ground-level retail; and two 12-story residential towers with 335 apartment units on the George Washington University campus. The three-phase project took nearly three years to complete.
Rock filled more than half of the space needed for the parking deck, requiring blasting and coordination with city police and fire departments and the hospital across the street. It also involved working with Washington Metropolitan Area Transit Authority officials, since trains running adjacent to the site were stopped during the blasts. Police escorted blasting crews and materials to the site and stayed to observe the three daily blasts.
The project consumed an entire city block and included as many as five radii at different parts of the building perimeter and courtyard. The concrete work required nearly 550,000 linear ft of post-tensioning cables for the radial slab edges located on three sides of the building.
“It has a pretty complicated geometry,” says Mike Wolski, project executive for Clark Construction Group of Bethesda, Md.
The building's three-story-tall lobby, bordered by two point-supported structural glass walls and two different radius walls, was no easy feat for the contractors. Successful completion, Wolski says, required close collaboration with the concrete and curtain wall subcontractors.
The height, spaciousness and Italian travertine stone of the lobby aim to create a sense of grandeur desired by both the owner and tenants, the project team says. The structural glass walls of the lobby allow passersby to see through the lobby to the courtyard on the other side.
The project team relied on three-dimensional building information modeling to coordinate the mechanical, sprinkler, HVAC and electrical components of Square 54, with subcontractors then meeting weekly to review shop drawings.
Square 54 is on track to achieve LEED-Gold certification. It features several innovative design elements, including a condensate water fountain and irrigation system in the courtyard, Wolski says. He adds that the scale of the project and its contribution to the area are impressive.
“It's a beacon in the middle of the city, a major development,” Wolski says.
Square 54, Washington, D.C.
Owner/Developer: Boston Properties, Washington, D.C.
GC & CM: Clark Construction Group, Bethesda, Md.
Lead Designer: Pelli Clarke Pelli Architects, New York
Structural Engineer: Thornton Tomasetti, Washington, D.C.
MEP Engineer: TOLK Inc., Fairfax, Va.
Executive Architect: Hickok Cole Architects, Washington, D.C.
Submitted by: Clark Construction Group