Engineers who have reviewed available information about the Surfside, Florida, condo collapse say investigations into its cause should focus on potential failures near the base of the building.
The disaster most likely resulted from a combination of foundation and structural problems, according to Mehrdad Sasani, a professor of civil and environmental engineering at Northeastern University. He said the collapse likely started at lower floors of the condo and could have been influenced by “40 years of exposure to salt, water and salt air and the indication of some level of damage in the garage at the lower floors of the building.”
Sasani said a range of other factors could have contributed to foundation and structural failures, including vibrations from recent construction work, heavy equipment on its roof and water damage associated with the building’s pool.
Joel Figueroa-Vallines, president of SEP Engineers, said he thinks it’s too early to reach conclusions, though he said video of the collapse appears to show that once the “pan-caking” of collapse began, columns at the center part of the building seemed to fail and a leaning effect occurred, followed by another part of the building falling.
He called all of the current analysis speculative but said that speculation “is leaning toward to the fact that this did not topple over. This sort of came straight down,” Figueroa-Vallines said.
He said he would focus an investigation on the foundation and the “podium level” of the pool deck. He also said he would look at the construction – “typically with pancake construction, there isn’t a lot of redundancy in the floor system.” “Flat slab systems generally have a little less redundancy. Not that that is the cause of the collapse, but once that collapse is initiated, that system will accelerate with gravity,” he said.
But he cautioned: “Typically in these cases there will not be what we call a definitive smoking gun; it’s more of a contributing factor scenario.”
Gregg Schlesinger, a Fort Lauderdale, Florida-based contractor and attorney who focuses on construction design, said the focus of any investigation should be on the columns, beams and slab at the foundation of the building.
“Did the building fail structurally? Yes. What makes up the structure? Concrete and steel. Did that fail? Yes. Why did it fail? … It was compromised. What portions were compromised? In the pictures [in the 2018 report], we definitely see a column that’s structurally compromised,” Schlesinger said.
Other likely contributing causes: seismic loads from construction next door, which could degrade the structural capacity, as well as roof loading, which may have involved a “point load,�� where equipment wasn’t scattered but was a dead load of equipment in one area that adds forces down through a compromised column. Also, the building is settling – the ground is settling and that could add additional forces to a compromised structure.
“Each one of these items is a straw. It’s a piece of evidence. It’s a clue. Can I say, ‘Well it was 23.3% responsible?’ No.”
“You know who will make that determination? Jurors. There will be, what I expect, a couple-months-long trial,” Schlesinger said.