Maintaining the historical façade of the country’s oldest hospital, while adding a new ambulatory care facility in limited space, posed a major design challenge. A 15,000-sf (1,400-sm) atrium lobby provided the solution. This unique 300-ft (91-m) long atrium stretches over a city block and consists of glass from floor to ceiling, allowing passerby to look through and see the original Bellevue entrance, built in 1736. Skylights also punctuate the ceiling giving the lobby an almost park-like feeling.

A major structural challenge in designing the 67-ft by 175-ft (20-m by 53-m) atrium was ensuring that the new building and the addition, two separate structures, could move independently of each another. For example, during an earthquake the existing building will likely sway at a different rate then the new building. This was accomplished by installing structural arms with smooth, flat upper surfaces that stick out past the face of the existing structure. The upper ends of the skylight trusses were equipped with a short pedestal with a lower surface covered in Teflon. In this way, the truss end can slide upon the smooth upper surface of its supporting arm, insuring that the two structures move independently of one another.