‘You don’t see buildings falling down in America.’ So why did Surfside tower crumble?

Before tragedy struck Thursday, the possibility of a residential condo tower in Miami-Dade County collapsing without warning seemed almost preposterous. Inspections and sound building practices were supposed to ward off such catastrophes. People were supposed to go to sleep at night knowing their homes were structurally sound.

But after the Champlain Towers South building in Surfside partially collapsed early Thursday, leaving rescue workers scrambling to save lives and account for more than 100 missing people amid the rubble, speculation ran wild and questions loomed large: How could this happen? Could it happen again?

There are no official answers yet. Those could take days — or much longer — to emerge. As of Thursday evening, Surfside town officials had not yet released any public records that could shed light on potential problems at the building.

Surfside Mayor Charles Burkett told reporters he was as stunned as anyone.

“It’s less likely than a lightning strike,” he said. “It just doesn’t happen. You don’t see buildings falling down in America.”

Several engineering experts, speaking from experience and reviewing chilling surveillance footage that showed the northeast, beachfront portion of the building collapsing around 1:20 a.m. Thursday, suggested a number of factors could have played a role, including saltwater corroding the concrete and potentially weakening beams that hold up the structure.

But while a critical, county-mandated process designed to catch any serious structural damage was underway at the Champlain Towers South, it was not yet complete. The 12-story, 136-unit building was erected in 1981 and was still early in its recertification process, which is required for most non-single-family structures countywide once they turn 40 years old.

In response to a Herald request for 40-year inspection documents, Town Clerk Sandra N. McCready said the town has not yet received any from the building owners.

“While the Champlain Towers had begun the 40-year recertification process, the 40-year inspection report had not yet been generated or submitted to the Town,” McCready said in an email.

The engineer retained by the Champlain towers as part of the recertification process was Frank Morabito, according to an attorney for the building’s condo association. Morabito could not be reached for comment Thursday.

The Herald has also requested construction permits, blueprints and architectural plans, and records of any building inspections or code violations logged by the town.

Recertification process was underway

The recertification process mandates that, once a structure turns 40, its owners must hire a registered architect or professional engineer to do electrical and structural inspections within 90 days of receiving official notice from the town.

If repairs are found to be necessary, the owner gets 150 days to complete them. The costs of repairs can be apportioned among the unit owners. And if the town’s building official determines the building to be unsafe, the case gets forwarded to the county’s Unsafe Structures Board for review.

Buildings then repeat that process every 10 years after the initial 40-year review.

“The bottom line is that’s not an old building, and 40-year inspection or not, that kind of thing should not be happening,” said Burkett, the mayor.

It’s not clear what stage the review process had reached and whether anything had been flagged at Champlain towers, which consist of three adjacent buildings near 88th Street and Collins Avenue.

But Town Commissioner Eliana Salzhauer told the Herald that the Champlain South building’s roof was being redone, and that James McGuinness, the town’s building official, had been there just a day earlier to monitor the progress.

Salzhauer added that the Champlain North building is almost identical to the South building, and she worried whether residents in the north tower might also be in danger.

“The loss of human life is horrible,” Salzhauer said. “But it’s also important to know why this happened, and what we can do to prevent this from happening again.”

Could it have been a sinkhole?

Miami-Dade County Mayor Daniella Levine Cava told reporters Friday morning that there was no confirmed sinkhole beneath the condo building that crumbled.

But the sudden, unexpected nature of the building’s collapse left officials and experts wondering about the possibility.

Jason Borden, the Florida regional director at O&S Associates — which bid unsuccessfully last year to perform the 40-year inspection at Champlain South — said he did an hour-long site visit in January 2020 and “didn’t see anything alarming or out of the ordinary.” The property manager believed the roof should be repaired or replaced, Borden said, and there were some cracks in the ceiling of the parking garage below street-level, as well as in the stucco that coated the building’s concrete walls.

But he didn’t see anything that seemed to put the entire structure at risk.

“My suspicion is that there was something going on there that was not detectable,” Borden said. If a sinkhole were to open up beneath a building, he said, “you don’t know it’s gonna happen until it happens.”

Borden said reviews of the underground structural integrity of buildings, including during the 40-year recertification process, are rare, in part because going underground is a “very pricey, very complicated” process. The bulk of a 40-year inspection is visual, he said, and excavations would likely only be done if there were visible evidence of shifting or movement in the foundation.

Borden’s firm submitted a proposal for the 40-year review in March 2020 before being told the firm was not selected. Borden said Champlain South management was proactive in initiating the process, given that the building didn’t reach its 40-year birthday until 2021. The town could have provided notice to the building anytime in the first six months of the year to trigger the 90-day window for its owners to complete an inspection report.

McCready, the town clerk, did not immediately respond to a request for information regarding if and when that notice was provided.

O&S Associates completed work earlier this year to replace the balcony guardrails at Champlain East, an adjacent condo tower that was built about 25 years ago. That project wasn’t related to any concerns about the structural integrity of the building, Borden said.

Was the building sinking?

Some have speculated that the problems could have started in the ground, but the author of a paper showing that the Champlain Tower building sunk at a slightly faster rate than its neighboring buildings, a process known as subsidence, cautioned that his research was a mere snapshot in time.

The April 2020 research paper compared subsidence in Norfolk, Virginia, to Miami Beach and found that Miami Beach experienced very little subsidence overall. FIU professor Shimon Wdowinski and his co-author found Champlain Tower sunk into the ground at a rate of about two millimeters a year from 1993 to 1999.

“It was not that significant, we’ve seen much higher than that. But it stood out because most of the area was stable and showed no subsidence. This was a very localized area of subsidence,” he said. “We saw the movement in the 1990s. It’s not what you see today. You can extrapolate, maybe.”

Wdowinski said land subsidence alone would not cause a building to collapse.

Jeff Rose, a Surfside resident and contractor whose parents live in the building — and who, thankfully, were in Colorado when it collapsed — said he has performed condo renovations for various units in the building. Rose said work on the roof started about six weeks ago, and said concrete restoration was also underway to repair old or damaged concrete.

But Rose said he hadn’t seen anything out of the ordinary there.

“I didn’t notice anything I haven’t seen in many other buildings in South Florida,” Rose said.

Salzhauer said one resident of Champlain South told her that, while construction was being done over the past few years on the building next door — 8701 Collins Ave., known as Eighty Seven Park — the Champlain structure was “shaking” and there were “cracks” in the building as a result.

Norma Arbide, who has lived in the North tower since 1987, told the Herald the construction next door caused tenants to complain about shaking in their building last year.

“The tenants in South were complaining a lot because their building was shaking and vibrating when they were digging and blasting at the construction site,” Arbide said.

The maximum building height in Surfside is 12 stories. Eighty Seven Park, which is located in Miami Beach, is 18 stories tall.

Rose and Salzhauer said residents at Champlain also had concerns about water leaking from a second-floor pool deck into the parking garage below.

It wasn’t clear Thursday whether those issues had anything to do with the collapse of the beach-facing portion of the condo, which affected about 55 apartment units. By evening, 99 people were still unaccounted for, officials said.

‘Concrete cancer’

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 behind the south tower 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.”

Batista, who has worked as an engineer in South Florida for 30 years, said that older condo buildings, apartment complexes and hotels near the ocean routinely deteriorate from exposure to salt water and other elements.

Atorod Azizinamini, chair of the FIU College of Engineering and Computing’s Department of Civil and Environmental Engineering, said such building collapses are exceedingly rare and usually involve a “perfect storm” of multiple factors.

“Usually these collapses are a result of some mistakes, maybe some negligence or some unusual events that might take place,” Azizinamini said.

Kevin DuBrey, the director of project management at Hillman Engineering in Fort Lauderdale — which has conducted 40-year inspections at other buildings — told the Herald that saltwater can get into the concrete of oceanfront buildings and corrode the steel inside.

He said he has inspected buildings where evacuations were needed because walls had to be replaced, but never because of the immediate potential for collapse.

“Usually buildings don’t get to that point,” he said. “Typically that would be something you’d probably know about in advance.”

While he was not familiar with the recertification at the Champlain Towers South, Batista said it has been his experience that South Florida condo associations often put off expensive structural improvements to their buildings because of the multimillion-dollar fees to pay for them.

“When an engineer says you need concrete repairs and it’s a structural issue, they should take them seriously,” Batista said. “I’ve seen it over and over again, and the can is just kicked down the road.”

Azizinamini, the FIU engineering chair, said Miami-Dade County should perhaps reassess its 40-year recertification process, especially for structures in coastal areas. Generally, building officials don’t inspect structures after they receive initial approvals to be built and before the 40-year mark, unless residents or owners flag specific concerns.

“I think we need to do a better job in our inspections,” he said.

Azizinamini said it could take “months” to determine what happened, a process that will involve investigators reviewing design plans, taking samples of concrete, talking to building designers and ultimately creating a computer model to simulate the collapse.

A ‘pancake collapse’

What is commonly known as a “pancake” collapse looks eerily similar to what happens to a building when it is demolished with dynamite, said John Pistorino, an engineer with a 50-year career in Miami who was instrumental in writing the 40-year recertification policy and other building safety laws.

“Condo residents will be frantic but these buildings are built so strong for our South Florida coastal conditions and hurricanes that this should never happen and it must be something unique to that tower,” he said. “It is so dramatically unusual that it’s hard to compare to anything other than a building going down in a city in a state of war.”

Pistorino said his firm was receiving calls all day from alarmed clients who own or live in high-rises but that there would be no answers until after a forensic investigation.

“It’s a mystery right now but you can go to sleep at night because our buildings are designed with heavy safety factors,” he said. “We will find out what really happened.”

Previous building collapses with fatalities that he has investigated were caused by a combination of problems, Pistorino said.

“Was there ongoing settlement, shifting of the ground that affected the foundation? Spalling and contaminated concrete? A water table or flooding issue? An overloaded roof? Cracking caused by construction next door?” he said. “That’s all speculation at this stage and those explanations seem unlikely. This was a 40-year-old building and we’ve got lots of structures over 100 years old that will last indefinitely if they are maintained.”

Structural engineer and retired building inspector Gene Santiago said video of the Champlain collapse struck him as “really strange.”

“The perimeter columns seem to have failed first and dragged the rest with them,” he said. “I’ve seen it in demos where it pancakes downward — bam, bam, bam.”

Santiago recalled how mistakes, lack of inspection and construction worker errors caused the collapse of a South Miami parking garage and a Hialeah apartment building years ago but that those were under construction when they failed.

Some of the theories as to why the Champlain tower collapsed “don’t seem plausible at this early juncture,” he said.

“Salt can seep into the concrete, and I’ve been on inspections on the beach back in the 1970s where there was no reinforcing left, but that sort of concrete cancer is rare today and it takes years and you would notice it,” Santiago said. “Roofing material and equipment is heavy, but a catastrophic failure caused by overloading doesn’t seem logical.”

Santiago continued: “Pilings driven 40 feet down would not necessarily be a concern, depending on the foundation. And vibrations caused by heavy construction are felt by residents but if that caused cracks they would be evident. None of this would be invisible over time, especially in a condo where everyone is typically observant and vigilant in their complaints.”

Pistorino drafted the county’s building recertification rules after the 1974 collapse of a downtown office building leased by the Drug Enforcement Administration.

“It was a 30-year-old building compromised by the corrosion of steel in our harsh environment and at least four people died as a result,” Pistorino said. “The concrete had salt in it, which rusted and expanded the columns and beams until they lost their support capacity. We said, ‘How do we prevent this from happening again?’ and decided to require inspections at 40 years and every 10 years after that. Since then, we also know exactly what to look for and how to do concrete restoration.”

The 1981 collapse of the Cocoa Beach Harbor Cay condominium that killed 11 workers when they were completing the roof was caused by errors in design, shoring and construction techniques and led state engineers to write the threshold building law that requires rigorous inspection during the construction process, Pistorino said, citing a number of local projects on which he has done repairs, inspections and investigations.

“There are protocols in place today that serve as an incentive for building owners to maintain the structure and envelope of a building,” he said. “Put your first priority on the structure, not the marble floors, and it will last.”

Amid the volleys of social media speculation were suggestions that the collapse could be terrorism related.

Federal authorities told the Herald there is zero evidence of that.

Miami Herald staff writer Alex Harris contributed to this report.