Capitol Crossing is a 2.2 million square foot development occupying the air rights to the 6.8 acre platform above Interstate 395 in the heart of Washington, D.C.. The three block mixed use development campus comprises office, retail and residential components. The project aims to reconnect the otherwise empty space above I-395 into three new city blocks, thus fulfilling Pierre-Charles L'Enfant's original vision of the city.

The firm was engaged by long-time client, Property Group Partners, for the design of two North Block buildings. 200 and 250 Massachusetts Avenue and are each twelve stories high, clad in a glass and polished stainless steel curtainwall assembly and are connected at the second level by a fully enclosed pedestrian bridge. A fifty-five foot wide Pedestrian Way which contains two glass enclosed eco-chimneys runs North-South between the two building structures and provides a lively food and retail environment. Half way down the length of the Pedestrian Way, suspended glass screen walls create prominent entrances to the 200 and 250 Mass Building Lobbies. The 250 Mass Lobby is also accessed below a suspended glass screen wall along Third Street. Both buildings have green roofs with outdoor terraces with panoramic views to the Capitol and Washington Monument. The 250 Mass building form breaks into two elegant towers on the fifth floor with a tree lined terrace separating the two towers. Parking for 1,146 cars with future infrastructure for charging stations occurs below grade for the full three city blocks on the west side of I-395.

The exterior of 200/250 Mass Ave is composed of two distinct curtainwall assemblies. A majority of each elevation has full height floor to floor triple glazing captured in stunning polished stainless steel frames with the towers corners and recesses clad in full height frameless triple glazed units. The subtle contrast of curtainwall types gracefully accentuates the buildings geometry. At every floor level, fritted glass fades into clear glass at the height of 3'-6". This all happens on top of a two story glass and granite pilastered base topped off with a polished stainless steel cornice.

The multi-story Lobbies present a stunning palette of finishes with large, vertical expanses of honed white Lasa Venato marble from Italy that are framed with textured finish stainless steel trim and accent lighting. The honed Jet Mist granite floors with stainless steel strip inlay draws you into the space. Each building Lobby has a beautiful stone and glass concierge desk. The 250 Mass Lobby is topped with two skylights which bathe the lobby in natural light. The elevator cabs are finished with textured mirrored glass and stainless steel trim and railings. The elevators lobbies and cabs are equipped with touchless Destination Dispatch technology.

These two LEED Platinum projects incorporate numerous assets to enhance the project’s sustainability. The 45,108 ft² of green roof mitigates the heat island effect and addresses storm water runoff. Advanced energy recovery systems, indoor air quality controls, water conserving plumbing fixtures, and the elimination of supplemental irrigation help minimize consumption of energy and resources. The insulated glass unit enclosure wall assembly with the latest technological advances provides maximum thermal efficiency. The Pedestrian Way features two glass clad eco-chimneys, which exhaust the below-grade parking level exhaust. The skylights on both buildings and the Pedestrian Bridge roof are part of a smart glass technology program controlled by each building’s intelligent glass control system.