Sun Sentinel Palm Beach Edition
Did drilling next door damage tower?
In the spring of 2016, residents of Champlain Towers South flooded complaint hotlines to fume about construction activity at the neighboring Eighty Seven Park project that had jostled their walls, closed their pool and coated their balconies in dust.
As the complaints were spiking in mid-March, a team of consultants working for the developers of the luxury 18-story condo next door were just wrapping up a report on the vibrations caused by construction crews driving sheet piles — a sort of subterranean retaining wall — into the ground directly south of Champlain Towers, at Collins Avenue and 87th Street, which divides Miami Beach from Surfside.
A report obtained by the Miami Herald showed that the vibrations exceeded the developers’ own target limits along Champlain South’s southern wall, including the span where the pool deck would cave in to the garage below five years later. The deck failed minutes before the tower collapsed on June 24, leaving 98 people dead.
The report, commissioned by developers, was based on readings from two seismographs positioned on the ground near Champlain Towers’ southernmost perimeter wall. Developers set a conservative threshold for maximum intensity of shaking at the wall, which should have prevented even the most superficial cosmetic damage, according to mining industry standards. Most of the readings along the wall came in over that limit, but under levels that would do significant damage, according to mining industry standards.
The vibration levels recorded
at Champlain’s southern perimeter were above limits used by the Federal Transit Administration to prevent damage to reinforced concrete.
Still, tremors from five years ago could not have been the ultimate cause of the June collapse, and readings along the wall were still well below levels likely to damage structural concrete, said Dr. Manoj Chopra, a geotechnical engineer with the University of Central Florida. There would be no reason to suspect the degree of shaking noted in the report would harm a healthy structure, he added. But the southern edge of the Champlain pool deck was not in good shape.
Overstressed from poor design and questionable construction, and weakened from years of water damage and inadequate repairs, the deck was already teetering on the edge.
In 2016, Eighty Seven Park developers drove sheet piles 10 to 12 feet south of the deck, and any vibration at such close range could have worsened conditions that eventually led to the collapse, experts told the Herald.
“What vibrations would have done is aggravate the situation,” Chopra said. Under a certain amount of strain from damage, bad construction and poor design, “if you shake it then definitely the vibration will have an effect,” he said.
The degree to which the drilling at Eighty Seven Park might have contributed to the Champlain Towers collapse has become a point of contention in litigation that has unfurled in the wake of the tragedy. The litigation casts a wide net, seeking to apportion responsibility and collect compensation from contractors, consultants and others targeted by plaintiffs’ attorneys for actions that they say may have contributed to the collapse.
Eighty Seven Park is listed in a handful of the 40 or so lawsuits, a spokesman for the development team said. The developers of Eighty Seven Park maintain their project “had nothing to do with the collapse,” the spokesperson said in a statement to the Herald.
The 2016 vibration monitoring report commissioned by the developers concluded that, although readings exceeded the target limit set by the developers, it wasn’t enough to do structural damage to the property next door. NV5, the subcontractor responsible for the vibration monitoring for Eighty Seven Park, told the Herald, “the vibration monitoring results did not warrant any action.”
Photos from a 2016 visual inspection commissioned by the developers show concrete at Champlain South was cracking prior to construction commencing at Eighty Seven Park. Inspectors noted superficial damage along the southern wall.
Condo board documents from the time also acknowledged that heavy planters along the southern pool deck had leaked water for years and caused damage to the concrete below.
The collapse also exposed damage inside the pool deck slab where it connects to the southern wall that likely wouldn’t have been visible prior to the cave-in, said Dawn Lehman, professor of structural engineering at the University of Washington and consulting engineer to the Herald. Lehman, who examined photos of the collapse site, said the slab damage pattern along the southern wall was not uniform, indicating that some areas had sustained damage prior to the collapse.
“Photographic evidence shows that it was damaged such that the concrete is broken into large chunks,” Lehman said. That’s different from other areas that disconnected during the collapse that didn’t show “any ‘rubble like’ damage,” she said.
But there likely wasn’t just one single cause of the pre-existing damage to the slab, which was more like the cumulative result of various stressors, Lehman said. One of them could have been vibrations from construction next door, she said. But the measurements in the report are “just borderline,” according to Eduardo Kausel, a retired Massachusetts Institute of Technology professor who specializes in soil dynamics. “I seriously doubt that had anything to do with the structural damage,” Kausel told the Herald.
Vibration readings were not taken at any other time during construction, even when the foundation piles were driven, according to the developers.
‘I have never seen that report’
In the months leading up to the construction of Eighty Seven Park, Champlain Towers South preemptively hired an attorney to demand “a reasonable compensation package for the construction and unavoidable nuisances that will undeniably result from” the development project, according to his letter to developers.
In the November 2015 letter, Champlain South’s attorney Robert Zarco flagged a concern about “potential structural damage to Champlain Towers stemming from the driving of steel sheet piling into the ground.” After construction crews finished driving the sheet piles and the building’s foundation, representatives for Champlain South followed up with a $2.4 million demand in May 2016 for cosmetic repairs and clean up, but didn’t mention any structural concerns. There’s no indication that representatives of Champlain South were ever made aware of the report that showed vibrations from construction had exceeded the developer’s limits. “I have never seen that report,” Zarco told the Herald.
He said he was specifically told to avoid structural claims. “They said we’ll handle structural at the time of the 40-year [inspection],” he said, referring to the structural review all large condo buildings in Miami-Dade undergo at that age. Champlain South was due for its 40-year recertification this year.
One former condo board member, who spoke on the condition of anonymity, told the Herald that residents were complaining in droves about the nuisances associated with the construction, and that the board was unable to do much with the complaints. Surfside town officials often deferred to the city of Miami Beach, which had permitted the construction but did not come down hard on violations, the board member said.
“The key people responsible for addressing the issues each had their own agenda and turned a blind eye,” the former board member said. Data from the vibration report could have quantified some of the residents’ concerns.
The March 2016 vibration report, which was prepared by GeoSonics, a subcontractor of NV5, detailed 35 readings taken to measure vibration along Champlain South’s perimeter wall during the installation of sheet piles between March 3, 2016 and March 14, 2016. All but six exceeded a target level of 0.5 inches per second.
The 0.5 inches per second target — a measurement of the movement of sediment at a given location — was based on studies by the U.S. Bureau of Mines that found consistent vibration at that level can cause cosmetic damage to plaster. A higher threshold is typically used to gauge the potential for structural damage, according to experts.
NV5, an engineering company based in Hollywood, cited a figure of 3.0 inches per second in its report as the rate at which damage to “block and mortar” is possible. None of the readings along the pool deck exceeded 1.0. The Federal Transit Administration standards use 0.5 inches per second as the limit for preventing damage to reinforced-concrete.
The developers maintain that the vibration report absolved Eighty Seven Park of having any impact on Champlain South with their construction, and that engineers checked for indications of damage at the time.
“We conducted a visual inspection on the south side of the wall, which did not reveal any issues from the installation of the sheet piles,” said the spokesperson, who insisted on anonymity. “By setting the benchmark at a conservative .5 in/sec., the contractor was able to keep all of the vibrations below the safe levels of vibrations for residential structures set by the U.S. Bureau of Mines,” the spokesperson said. “At no time did the vibrations approach levels that would have caused structural damage to CTS.” But lawyers for the collapse victims say it’s too soon to know.
On Wednesday, attorneys for the developers turned over the report to victims’ lawyers as part of a court-ordered release of documents. Stuart Grossman, an attorney and liaison for a group of lawyers representing the victims, said Thursday that a team of experts hired by the group is reviewing the report.
‘Very many complaints’
Construction of Eighty Seven Park roiled Champlain South residents. In January 2016, the condo association board sent out a building-wide email with the construction noise complaint hotline for Miami Beach. By March, the complaints were piling up.
“We have received the very many complaints and concerns you each have expressed to Board Members as well as the Management Office,” the board wrote to residents in an email on March 14, the final day of vibration monitoring by NV5. “These have included the recent oil on cars parked on the street level, the vibrations to the building, the dust and debris which is preventing access to balconies, the noise from the very early morning food truck with blasting music, the concern that workers begin to drill at 7 a.m. and the debris and noise caused by the auger that is drilling directly next to the pool which is preventing residents from going to the pool.”
The project stretched on for years and continued to cause ire among Champlain South residents.
In January 2019, a condo board member wrote to Surfside’s then-chief building official, Ross Prieto, complaining that the Eighty Seven Park project was “digging too close to our property and we have concerns regarding the structure of our building.”
The email that board member Mara Chouela sent to Prieto included two pictures of a backhoe working against Champlain South’s southern wall along the property line. Less than a half hour later, Prieto responded to Choluela’s request to stop by and check on the situation.
“There is nothing for me to check,” he wrote back. “The best course of action is to have someone monitor the fence, pool and adjacent areas for damage or hire a consultant to monitor these areas as they are the closest to the construction.”