Three years before the fatal collapse of the Champlain Towers South condominium complex near Miami, a consultant found alarming evidence of “major structural damage” to the concrete slab under the pool deck and “abundant” cracks and fragments in the pillars, beams and walls of the parking garage underneath the 13-story building.
The engineer’s report helped formulate plans for a multi-million dollar repair project that was due to begin soon – more than two and a half years after the building managers warned – but the building catastrophically collapsed in the middle of the night Thursday, trapping sleeping residents in one huge pile of rubble.
The complex’s administrative association had announced some of the problems following the collapse, but it wasn’t until city officials released the 2018 report late Friday that the full nature of the concrete and rebar damage – most of it likely caused by years of exposure to the corrosive salty air along the way – became clear South Florida coast – became shockingly evident.
“While some of this damage is minor, most concrete damage needs to be repaired in a timely manner,” wrote consultant Frank Morabito in his October 2018 report on the 40-year-old building in Surfside, Florida. He gave no indication that the structure was in danger of collapsing, but noted that the repairs required are aimed at “maintaining the structural integrity of the building and its 136 units”.
Kenneth S. director, an attorney who represents the resident-run association that operates the building, said this week that repairs would begin based on extensive plans drawn up this year.
“They were just about to start,” he said in an interview, adding that the process would have been handled much differently if owners had had evidence of corrosion and crumbling – mild cases of which are relatively common on many coastlines in buildings – posed a serious threat.
However, Eliana Salzhauer, a Surfside commissioner, said that while the cause of the collapse was unknown, it appears to her that the problems identified by the engineer in the 2018 report may have contributed to the structural failure.
“It is disturbing to see these documents because the housing management was made aware that there were problems,” said Ms. Salzhauer. “And the documents show that the issues were not addressed.”
Investigators have not yet identified the cause and are still waiting for full access to a location where rescue workers have urgently searched an unstable pile of rubble for possible survivors. Experts said the process of evaluating possible failure scenarios could take months, including checking individual building components that are now buried in rubble, examining the concrete to assess its integrity, and examining the subsurface to see if there is a sinkhole or other subsidence were responsible for the collapse.
The building was in a recertification process – a requirement for 40-year-old structures that have withstood the Florida coast hurricanes, storm surges, and the corrosive salty air that can penetrate concrete and rust the rebar and steel girders inside.
The 40 year requirement was introduced in 1974 after an earlier building collapse in Miami.
Declining to comment this week, Mr Morabito wrote in the 2018 report that the aim of his study was to understand and document the extent of structural problems that would require repair or refurbishment.
“These documents will enable condominium management to adequately assess the overall condition of the building, inform tenants of the potential impact, and provide safe and functional infrastructure for the future,” he wrote.
On the ground floor of the complex, vehicles can drive in next to a pool deck where residents can relax in the sun. Mr Morabito said in 2018 that the waterproofing under the pool deck and driveway had failed “causing significant structural damage to the concrete structure slab under these areas”.
The report added that “failure to replace waterproofing in the near future will cause the extent of concrete deterioration to expand exponentially”. The problem, he said, was that the waterproofing was being laid on a flat concrete slab that wasn’t sloped enough for water to drain, a problem he called a “big mistake” in the original design. The replacement would be “extremely expensive”, he warned, and would be very annoying to residents.
In the parking garage, which is mostly on the lowest level of the building, part of it below the pool deck, Mr Morabito said there were signs of distress and fatigue.
“Numerous cracks and flakes of varying degrees were observed in the concrete columns, beams and walls.” Mr. Morabito wrote. He added photos of cracks in the pillars of the parking garage, as well as crumbling concrete – a process engineers call “chipping” – that exposed steel reinforcements on the garage deck.
Mr. Morabito noted that previous attempts to touch up the concrete with epoxy had failed, resulting in more cracking and chipping. At one such point, he said, “New cracks radiated from the cracks originally repaired.”
The report also identified a number of other problems: local residents complained of water leaking through their windows and balcony doors, and the concrete on many balconies also deteriorated.
After watching a surveillance video showing the building’s collapse, Evan Bentz, a professor at the University of Toronto and an expert on structural concrete, said the cause of the collapse may have been somewhere near the building around the parking deck . Although he hadn’t seen the 2018 report at the time, he said that such a breakdown could have several possible explanations, including a design flaw, a material problem, a design flaw, or a maintenance failure.
“I would be surprised if there was only one cause,” said Bentz. “There would have to be several reasons for it to fall like this.”
Other concerns about the complex have been raised over the years. A resident filed a lawsuit in 2015 alleging poor maintenance allowed water to enter her home through cracks in an exterior wall. Some residents expressed concern that demolitions during construction in a neighboring complex had shaken their units.
Researchers analyzing space-based radar had also identified land that sank on the property in the 1990s. The 2020 study found subsidence in other areas of the region, but on the east side of the barrier island that Surfside is on, the condominium complex was the only place where the problem was found.
The Champlain Towers South project proposed in the late 1970s, according to records, was completed in 1979 with its architectural and structural designs. At the time, people flocked to South Florida to live and play, and developers were looking for larger complexes that people could place right on the beach.
An almost identical outbuilding – Champlain Towers North – was built a few hundred meters up the beach that same year. It was not immediately clear whether the problems raised by the engineer on the southern project were also found in the other buildings.
Surfside Mayor Charles W. Burkett said Friday that he was concerned about the stability of the north building but was “philosophically uncomfortable” about evacuating people.
“I cannot tell you, I cannot assure you that the building is safe,” he said at a meeting of the city commission.
The collapse stunned industry experts in the Miami area, including John Pistorino, a consulting engineer who devised the 40-year reinspection program when he was advising for the county in the 1970s.
He pointed to other regulations that have been in place since then, including requirements that an independent tall building engineer must verify that construction is going according to plan.
Mr. Pistorino did not want to speculate about the cause of the collapse. However, he said that while some buildings in the area had quality issues, serious defects were unusual and usually easy to spot with blatant cracks or other visible problems.
“This is so outside the norm,” said Mr Pistorino. “That’s something I can’t fathom or understand what happened.”
James Glanz and Joseph B. Treaster contributed to this report.
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