NIST Releases Technical Findings on What Caused the 2021 Partial Collapse of Champlain Towers South

Today the National Institute of Standards and Technology’s National Construction Safety Team released its technical findings on the cause of the partial collapse of the Champlain Towers South building on June 24, 2021, which took the lives of 98 people. Following an extensive technical investigation, the team has concluded that the collapse began in early June 2021, when two connections between garage columns and the pool deck failed. These initial column failures caused cracks to grow and loads to redistribute in the pool deck over the next three weeks, resulting in the transfer of their loads to adjacent slab-column connections that were not strong enough to support them. This led to the larger catastrophic collapse on June 24.

Investigation co-leads Judith Mitrani-Reiser and Glenn Bell explain the findings in a video presentation released today. The video includes a high-level introduction to the findings, followed by detailed technical explanations with visualizations, photographs and animations.

“When building structures are designed and built to required codes and standards, they have margins against failure, meaning they should be able to support much more load than they are expected to bear,” said Mitrani-Reiser. “In the case of Champlain Towers South, however, these margins against failure were too narrow from the start.”

Champlain Towers South was built in 1981 on the Atlantic coast in Surfside, Florida. It stood 12 stories high, plus a penthouse, and comprised three sections, which the NIST team refers to as the West, Middle and East parts.