Two days before condo collapse, a pool contractor photographed this damage in garage
https://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article252421658.html
The video shows sequence of collapse of the Champlain Towers South is simulated with a possible explanation for the failure illustrated.
On 24 Jun 2021 the Champlain South Tower collapsed at 1:15am. This is a 12 storey 126 unit condominium building in Miami Florida. It was built in 1981.
“The 3D animation to illustrate the building and structure is based on Architectural and Structural drawing made available by the town of Surfside. The events and sequences are based on key photographic evidence and eyewitness accounts. The engineering reports on the planned repairs have been used in preparing this analysis.
I have a career in designing and constructing buildings including experience in the USA. I caution that its still too early to know why it collapsed. This video is only a suggestion of the root cause of the failure.”
https://www.youtube.com/watch?v=hynHiWE818c