The Columbia University Medical and Graduate Education Building (CUMGEB), designed by Diller Scofidio + Renfro (DS+R) in collaboration with executive architect Gensler, is a 100,000 sf, 15 story, state-of-the-art educational facility. Leslie E. Robertson Associates is the structural engineer. The project's main feature is a southern facing 'Study Cascade' that contains interconnected study and social spaces to encourage collaboration between students. Envisioned as a vertical campus of stacked neighborhoods, the new building presents a welcoming and inviting atmosphere to its community. The facility incorporates technologically advanced classrooms, anatomy labs, a modern simulation center, and a mid-tower mechanical space. CUMGEB's main structural design challenge was to find vertical load paths through the Study Cascade that could respect the varied spatial planning of stacked neighborhoods while providing floor spans that could accommodate the tight deflection performances required for coordination with the curtain wall. The highly articulated façade is critical to the buildings architecture, which is organized to engage students with one another and with the neighborhood as a whole. A concrete structure is used because concrete construction facilitates the changing floor-to-floor slab edge positions required for the spaces and related facade, the concrete structure could be tuned to reliably meet the performance requirements, and concrete is flexible for coordinating a tightly integrated design. The Study Cascade structure has no perimeter columns, which results in a unique sequence of cantilevered concrete slabs. Engineering structure includes In-floor post-tensioned and high-strength rebar 'trusses', bonded post-tensioning slabs, cantilevered slab designs with tapered edges to reduce weight, V-shaped column, exposed self-consolidating concrete columns, and slab void formers which are used to reduce the self-weight of the structure and to allow for long spans efficiently formed without beams. CUMGEB is the first building in New York City to use this void former technology, which is manufactured by Cobiax.