NIST Reveals Causes of 2021 Champlain Towers Collapse

Animated Champlain punching shear illustration shows a column pushing up through a cracking concrete slab.

This animation illustrates how forces pushing down on a steel-reinforced concrete slab can cause it to bend and crack around a supporting column, weakening the connection holding the slab in place until it ultimately fails. National Construction Safety Team experts determined that this type of "punching shear failure" at two columns in the garage under the pool deck slab in early June 2021 led to the June 24, 2021, partial collapse of the Champlain Towers South building.
Credit:

NIST

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.

"> NCST Champlain Towers South Investigation | Technical Findings (June 2026)

NCST Champlain Towers South Investigation | Technical Findings (June 2026)
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