The condo in Surfside, Fla., that collapsed two years ago had a “severe strength deficiency” in its pool deck, with a design that failed to meet building codes and construction that did not follow its original plans, federal investigators said Thursday.
Concerns about the pool deck have surfaced repeatedly since the June 2021 collapse at Champlain Towers South that left 98 people dead, but the preliminary analysis from a federal team shows the extent of the problems uncovered so far. Crews are assessing whether a failure of the pool deck could have triggered the collapse of the mid-rise residential tower; at a meeting on Thursday, one investigator described that scenario as “somewhat a leading hypothesis” for now.
Investigators with the National Institute of Standards and Technology still have many more months of work ahead before reaching a conclusion about what caused the failure. Officials have described it as one of the most complex inquiries of its kind ever undertaken, in part because there was no obvious cause.
“This is a big safety issue for the country, so we have to get this investigation right,” Glenn Bell, one of the lead investigators, said at the meeting on Thursday, when team members briefed an advisory committee about the status of the case. “We cannot leave any stone unturned.”
The investigation has included interviews of witnesses, a review of historical records, testing of the building’s materials and the production of models assessing the building’s structural soundness. The team has looked at the original design and construction of the 40-year-old tower as well as all renovations and repairs; it has also examined the potential effects of corrosion, ground settlement and vibrations from construction nearby.
Crews have been unable to recover the system that stored the building’s security footage, but still hope to do so.
Officials say they do not anticipate completing their final report until May 2025.
The collapse in the early morning hours of June 24, 2021, came with little warning. Some witnesses reported that the pool deck area fell first, crushing vehicles in the parking garage below, and structural engineers said a failure there could have destabilized columns underneath the main part of the building. A large portion of the tower collapsed into a pile of rubble within minutes, before many residents were aware that something was amiss.
The investigators said on Thursday that the pool deck’s design lacked sufficient strength at and between many of its supporting columns. They determined that those problems were severe in many places, and that the design provided only half of the strength required under the original codes and standards.
And the pool deck had other problems. The steel reinforcement inside the concrete slabs of the pool deck was buried deeper in the concrete than the initial designs. Planters that were heavier and more extensive than originally designed had been added to parts of the pool deck, bringing more weight to an already under-designed system. Investigators have also been looking at the layers of sand and paving stones added later to the top of the deck, and at signs of corrosion in some parts of the steel reinforcement of the deck.
All those issues, the investigators said, left the structure with “critically low” margins to protect against failure. There are signs that the pool deck was showing distress — cracks in a planter and sagging concrete slabs — before the collapse, the investigators said.
“The conditions that existed in the pool deck slab at that time represented a serious safety concern for the building,” Mr. Bell said.
The investigative team has not ruled out other possible trigger scenarios, such as a problem in the tower itself. They continue to leave open the possibility of an explosion or vehicle crash being a factor, but have not found evidence of either.
Officials said they were not yet ready to issue any recommendations but planned to consider new guidance on construction practices, building codes, document-retention requirements and ways of assessing the safety of existing buildings.
The building, constructed in 1981, had many issues that have previously been reported, not only with the pool deck, but also with corroded columns, design errors and improper steel reinforcement. Three years before the tragedy, an engineer had warned of “major structural damage” at the complex, and a multimillion-dollar repair project was about to get underway when the collapse occurred.
Relatives of the victims, and those who survived the collapse, reached a $1 billion settlement in the case last year.
Securitas, a company hired to handle the building’s security, paid the largest portion of the settlement. The New York Times reported last year that the building’s security guard had not been trained in how to activate the building’s warning system.