Winthrop Center

Our approach to the structural design of this 53-story, 1.8M-SF mixed-use tower navigated between two competing priorities: complying with FAA height restrictions and maximizing rentable space. Upon initial permitting, comments from the FAA and the city required capping the project at 700 feet (213 meters), meaning we had to deliver the client’s 775-foot (236-meter) vision through a shorter tower. To address this, DeSimone selected cast-in-place concrete for the primary structure—an uncommon choice for a commercial tower in Boston, historically a steel town. By using concrete, which requires less space, we maximized floor-to-floor heights and added five floors beyond what would have been possible with steel.

The hybrid building program called for a combination of office floors at the base of the tower with residential floors above. To unify the incongruous column grids, we engineered a 20 million-pound “sky mat” at the 23rd floor, which transfers column loads from the residential floors above to the office floors below.

At street level, a stunning, three-story, through-block civic space, dubbed “The Connector,” includes a food hall, meeting rooms, and retail. This expansive public space through the building can host cultural events and fosters a vibrant street life by connecting to the surrounding Boston historic financial district and a series of public green spaces. To accommodate this large open space, we designed a steel-framed deck just above it—supported by concrete mega-columns—to create a platform for the tower above.