Champlain Towers South

A rendering shows punching shear as it occurred at the site.Thornton Tomasetti

On June 24, 2021, Champlain Towers South, a 12-story beachfront condominium in Surfside, Florida, partially collapsed, killing 98 people and injuring 11 others. To determine what caused the collapse, our forensics team reviewed the building design and performed linear and nonlinear analyses to simulate various collapse sequences. Our investigation revealed that some of the building’s columns were too small and that its column-to-slab connections were insufficient to prevent punching shear (a failure that occurs when a flat slab detaches from a column, in which the column appears to “punch” through the slab). These findings explained how the collapse progressed through most of the structure.

After the collapse, Florida enacted a statewide law requiring milestone inspections for buildings of certain types, sizes and locations. “We’re committed to safety,” says Senior Associate Lauren Millman, “so we’re educating owners, property managers and insurers about the new legislation and helping them fulfill its requirements.” To nurture transparency and long-term relationships in the communities we serve, we’ve also developed a web-based hub to help monitor their buildings’ health; remind them of necessary maintenance, repairs and inspections; and enable them to track their assets. One of our goals for the website – and the publication of our findings – is to inspire stakeholders to be more proactive about building safety.