“Appearing to reinforce the experts’ theory is the story of a resident who called her husband moments before the collapse to tell him she could see a crater in the pool area from the fourth-floor balcony of their ocean-front apartment. Then the line went dead, said Mike Stratton, who was out of town at the time. His wife, Cassie, is among the 156 people who are still unaccounted for.
Greg Batista, a professional engineer who specializes in concrete repair and worked on the Surfside condo’s pool deck in 2017, said that the way the building fell points to an initial collapse of the pool deck area into the parking garage, which then dragged down the other parts of the condo tower in a “domino effect.” Structural engineer and retired building inspector Gene Santiago agreed that was a probable trigger and pointed to a 2018 inspection, first reported by the Herald, that noted “major structural damage” below the pool deck.”
"Greg Batista, a professional engineer from Davie who specializes in concrete repair projects, said that after watching the Surfside condo tower collapsing to rubble in online videos, one potential structural flaw jumped out at him.
“Concrete spalling.” Here’s what it means.
Batista said that when salt water seeps into porous concrete, it causes the reinforced steel rods known as rebar in the support beams to rust and expand. In turn, the expansion breaks up the concrete and that weakens the beams.
It’s like “concrete cancer” spreading, said Batista, who worked on the planter boxes on the pool deck at the Champlain Towers South Condo building in 2017.
“Once the cancer spreads, the concrete breaks up and becomes weaker and weaker as time goes on,” Batista said. “My best guess is that’s what happened here. This building has a garage on the lower floors. If you have one column subjected to spalling, the no. 1 suspect here, it could fail. That one beam could bring down the whole building like a domino effect.”