Is that limestone under the water table? If it is, what good is it going to do?
Limestone 3-4 feet from surface is the norm in Dade county
Most Freepers think the sand is super deep....it’s not
The water table is not the determining factor
Few structure in coastal America 120 feet high that don’t penetrate the water table in their foundation
But few east of the Rockies have a bedrock this shallow as in SE Florida...
Bear in mind limestone ain’t granite
But this is a side track
Plenty of tall buildings are built into non bedrock foundations with super deep pilings
Like where I’m from in the Deep South clay...100-150 before rock
The issue here is not what sort of foundation host exists
It’s that something was deteriorating and nobody noticed
Could have been steel girders bored onto granite bedrock and if it deteriorates it falls
This was concrete pilings I think poured into limestone and a long pool leak soften the concrete.....I think.....seawater is usually bad for concrete though the Romans made ‘mortar and aggregate structures in water where salt water actually hardened it...
I suppose depends on the mix....maybe crushed shells helps with seawater....
I grew up in a contracting family that built buildings similar to this before we went strictly pipeline and plants
Water and sewer and oil and gas
We set foundations a variety of ways.....usually subbed to the site prep firm
And they always had to deal with water
Surface pumps or wellpoints that look like golf tees
My main message is contrary to popular assumption here....Miami has substantial bedrock which actually is on the surface in places....
I know this having lived there 88-94