Extending the Ground: The Tall Building as Public Continuum

This paper explores how tall buildings can operate as an extension of public space rather than only a privatized vertical architecture, using a trio-connected supertall proposal on Chicago's downtown lakefront as a design-based case study. The project was developed within a tall-building design seminar at the Yale School of Architecture led by Kyoung Sun Moon and addresses the design of a mixed-use high-rise incorporating office, residential, hotel, commercial, and public programs. Chicago's lakefront has historically functioned as a continuous public system, yet contemporary infrastructure, land scarcity, as well as coveted private developments along the waterfront have increasingly disrupted public access to the water. In response, the project proposes a vertical public ground that extends the civic logic of the waterfront upward into the tower. The design introduces three supertall towers interconnected by a large-scale public space structure serving both the tower users and the public. Instead of following the conventional solo tower model in which height correlates with increasing privacy, the project incorporates publicly accessible programs-such as museums, galleries, libraries, and indoor gardens-within a 250-meter-tall shared structure between independent hotel, office, and residential towers. A dual-core circulation system, one core mainly opens to the tower spaces and the other primarily to the shared public space structure, with exposed express elevators are employed in the public cores to make public access legible, direct, and spatially distinct from private uses. By reframing the tall building as public infrastructure, the paper argues for a new typology of vertical civic space applicable to dense urban waterfronts shaped by infrastructural constraints.