What to Know About the Building Collapse in Surfside, Fla.
https://www.nytimes.com/2021/06/24/us/miami-surfside-building-collapse.html
Forensics will determine what happened. A few things to note in the debris and remaining structures:
1. One video shows a hole large hole below the remaining structure to the south, partly filled with debris from the collapsed portion. Not clear if this is an underground garage or a cavity caused by erosion.
2. Concrete floor slabs were pulled away from the concrete core with rebars left protruding. Not clear if these rebars broke or were doweled into the previously-constructed core. Lack of concrete supports, continuous or curbed, below the slabs is significant.
3. One or two bright flashes at the top two floors next to the core are shown at the start of the video of the collapse. These could be main electrical cables snapping or gas explosions or both, the cables breaking producing sparks to ignite broken gas lines. That floor falling began the series of pancaking failures as excessive loads overcame designed capability of the slabs. This may be recalled as what happened at the WTC collapse.
4. There is no obvious lateral bracing in the debris. Maybe omitted due to the first section collapsing being embraced by the two adjoining components, or there may be shear walls below the debris.
5.Maybe far-fetched is the number of roof-top AC units which may have overloaded the roof slab and its fall led to failure of those below. These units are usually not heavy but it is unclear how many were original and how many were added later, with heavier units.
NY Architect, DOB Vet
If there is a cavity underneath the structure, that would be interesting. They didn't want to fix the problems, we been telling them this day would come for years.