An existing 5-story building was demolished at 500 D Street, SW in Washington, D.C. to construct National Square. Cardno provided structural engineering services for the new Class A 12-story, 365,000 sf office building that sits above three levels, 97,000 sf of below-grade parking. The high security office building is designed to meet Level III Security Protocols in accordance with the U.S General Service Administration’s Interagency Security Committee (ISC) Design Criteria including progressive collapse prevention making the building attractive to government tenants.
The facade is a precast, aluminum, and glass curtain wall. The lobby includes a 2-story atrium adorned with wood paneling, back-painted glass panels, and marble flooring finishes. A glass and metal canopy featuring LED lights illuminates the D Street entrance. The building is LEED Gold Rated and includes a 16,500 sf green roof. The location of the building in the Southwest Waterfront area provides views of the U.S. Capitol, monuments and additional landmarks.