MIAMI — A federal investigation has determined that structural failures in the pool deck of Champlain Towers South began about three weeks before the condominium partially collapsed in Surfside, Florida, on June 24, 2021, killing 98 people, the National Institute of Standards and Technology said.
NIST’s National Construction Safety Team released its technical findings on Monday, concluding that punching shear failures occurred at connections between two garage columns and the pool deck slab in early June 2021. This initial failure led to cracking and load redistribution in the pool deck, eventually causing adjacent connections to fail as they were not strong enough to support the shifted weight, according to the report.
The 12-story building, constructed in 1981, partially collapsed in the early morning hours, with the pool deck slab breaking away and triggering the failure of the middle and east sections of the tower. NIST attributed contributing factors to the original design and construction, including inadequate reinforcement and deviations from code requirements, as well as long-term issues such as corrosion.
“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,” Judith Mitrani-Reiser, co-lead investigator, said in a statement.
The findings indicate that signs of distress, including cracks and slab movement, were present in the weeks leading up to the collapse but went undiagnosed. The investigation involved analysis of physical evidence, historical records, computer simulations and witness accounts.
Champlain Towers South stood on the Atlantic coast in Surfside, north of Miami Beach. It comprised three connected sections. The collapse left only the western part of the building standing. Rescue and recovery operations lasted for weeks following the disaster.
NIST’s nearly five-year probe, one of the most extensive building failure investigations in U.S. history, highlighted vulnerabilities in older coastal structures. Officials noted that problems originated from the building’s design and construction era but were compounded over time.
Local authorities and building owners had identified maintenance issues in prior inspections, including in 2018 and 2021, but major structural repairs had not begun before the collapse. The report stops short of assigning legal blame, focusing instead on technical causes.
As of Tuesday, NIST officials continued to review implications for building codes and inspection practices nationwide. The full set of detailed technical reports is expected to follow. Victims’ families have called for greater accountability in the aftermath.
The incident prompted widespread reviews of condominium safety in Florida and other states with similar structures.
