The NIST National Construction Safety Team analyzed photographs, building maintenance records, and eyewitness reports to develop this graphic showing where cracks had been identified in the first-floor slab in the months and years before the 2021 partial collapse of Champlain Towers South. The cracks are noted in turquoise, while construction joints (where concrete slabs meet) that are of interest to the investigation are shown in pink. Note the concentration of cracks in the street-level parking and pool decks.
Miami-Dade County Open Data Hub/NIST
Recent interviews and analyses of test results and physical evidence by the National Institute of Standards and Technology (NIST) reinforce preliminary findings that the 2021 failure of the Champlain Towers South building likely started in its pool deck rather than in the tower itself. The investigation has also identified indications of the building's distress that were visible in the weeks before the partial collapse of the building in Surfside, Florida.
Investigative lead Judith Mitrani-Reiser and co-lead Glenn Bell presented an update on the NIST investigation today at a virtual meeting of the National Construction Safety Team (NCST) Advisory Committee. Their presentation summarized the investigation's activities and preliminary findings provided in previous updates, including an extensive video released in June 2025, and highlighted significant progress in the failure analysis since the June update.
Bell described the team's current efforts to advance its evaluations of potential failure initiation scenarios through computer simulations, supported by the results of large-scale structural testing and evidence of the building's distress in the weeks before failure. The team has also been refining its analysis of the impacts of steel reinforcement corrosion, concrete shrinkage, and improperly built construction joints in the pool deck slab.
According to Bell, the results of these efforts "indicate that it is more likely that the failure started in a pool deck slab-column connection."
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