Thornton Tomasetti is providing structural design services through design development for Torre KOI, a 67-story tower in Monterrey, Mexico that will be the country’s tallest when completed. Excavation is now underway for the 906-ft (276-meter) tall, 1.5-million-sf (140,000-square-meter) building designed by VFO Architects with Stark+Ortiz serving as the local engineer. Developer Internacional de Inversiones is our client. The mixed-use building will house offices, nine levels of parking and, from the 22nd floor, luxury apartments—dubbed “KOI Sky Residences”—which will feature panoramic views of the Cerro de la Silla, the Sierra Madre and the Cerro de las Mitras mountains. The structural system consists of post tensioned concrete flat slabs supported by concrete columns and a concrete shear wall core with post tensioned concrete waffle slabs at the garage levels. The core’s high aspect ratio posed a significant challenge for meeting wind acceleration limits. Full-story concrete belt walls at levels 21 and 61 will link the tower columns to the shear wall core to resist lateral loads and provide stiffness to minimize perceptible accelerations due to wind loads. The project will seek LEED Silver certification.