The answer won't be known until a forensic investigation is complete but there are a number of sophisticated sensing techniques and tests — sonar, radar, hand-held x-rays, salinity tests and magnetic imaging — that can help engineers assess conditions beneath inside a concrete beam or beneath the foundation.
Neither Miami-Dade County nor the state of Florida requires inspectors to use any of them.
With the death toll reaching 16 on Wednesday morning and expected to continue rising, some structural engineers and architects say the tragedy should serve as a catalyst to update Florida's dated building inspection laws — especially in coastal communities where rising water tables pose increasing threats.
"I hope this causes some discussion and hopefully something comes of it — at a minimum additional inspection requirements statewide," said Joel Figueroa-Vallines at SEP Engineers, an Orlando-based forensic structural engineer.
Miami-Dade Architect Kobi Karp said that just as Hurricane Andrew led South Florida, and eventually the state, to update its building codes, Champlain Towers can serve as the impetus for safer buildings.
"The opportunity that we have to learn from this is that we have a new day. We have that technology. We just need to implement it," Karp told CNN on Tuesday.
The most important change Florida could make to its building inspection law is to require that foundations and the subsurface conditions are tested, said Raul Schwerdt who owns RAS Engineering in South Florida, a structural engineering firm he runs with his son.
" New York, California and Chicago have required [foundation] testing, but Florida hasn't really caught up," he said.
No State Standard
Miami-Dade and Broward counties are the only counties that require aging high-rises to go through a reinspection after they reach 40 years of age. Those that fail to make needed improvements can lose their occupancy license. But everywhere else in Florida there is no routine inspection required after a building is built. And, across the state, there is no requirement at all to probe beneath the surface and beyond what is visual to the eye.
"To do a complete evaluation on a structure you need to include the foundation," Figueroa-Vallines said. "The building could be designed perfectly and if the foundation fails, the building is still coming down."
RAS engineers charges $2500 a day for forensic testing and the cost depends on the condition. They start with the superficial layers — testing the paint or the surface strength of the concrete — and then "follow the clues," he said.
When they reach the subsurface, they can test inside of the structure on the concrete and steel using a variety of imaging devices and chemical testing. Ground penetrating radar, hand-held x-ray machines and magnetic imaging wands can be used against a concrete wall or building slab.
"They can measure a wall's thickness and if the plan says half-inch and the instrument tells me it's one inch, that could tell me the rebar is corroded, because when steel corrodes it expands," Figueroa-Vallines explained.
In some cases, there even could be underground canals that are not detectable from the surface — like one RAS Engineers once discovered in a downtown building on Brickell Avenue, Schwerdt said. Depending on the construction, that can also erode the piles holding the foundation.
"These unusual situations are even more usual now because of this rising water," said Wolf Schwerdt, Raul's son. " South Florida should really be looking at testing all of these situations very seriously."
John Pistorino, who was an engineering consultant for the Miami-Dade County in 1974 when the 40-year-old DEA office in downtown Miami collapsed, killing seven employees. He came up with the idea of requiring buildings to be recertified when they reach that age.
Pistorino told Jim Defede of CBS 4 News that engineers trained in the process can see visual clues of subsurface problems.
"We always start to look at is if there is some evidence of a settlement where something is going on in the foundation," he explained. "If that's happening, then we can see it from above. The concrete will crack in a certain pattern. We call them shear cracks. And even though they're very hairline cracks, an engineer who understands the design of these buildings and who has been involved in the construction can look at these cracks because they make a specific pattern."
Still, Pistorino said he expects the Champlain Towers collapse will lead to updates and changes to the recertification process.
Sen. Jason Pizzo, a Miami Democrat whose district includes Surfside, said he is working with engineers to gather input about how to update Florida's law. He said he will have a draft by July with legislators addressing it during committee meetings in September.
"The problem with our recertification process is it considers where a building is standing in a vacuum. It does not consider where it is located," he said.
With its high water table and vulnerability to sea level rise, the state needs to update its reinspection process to include more factors, especially for buildings close to the shore line and flood zone, Pizzo said.
"You don't buy a raw piece of ground anymore without doing very simple soil borings to see if there's contamination," he said. "We should do the same thing with buildings."
Miami-Dade Exploring Improvements
Gov. Ron DeSantis and legislative leaders have expressed their sympathies to the victims and support for the search and rescue teams. But they all have been reluctant to call for any change to state law — at least before the causes of the unprecedented collapse are pin pointed..
In an interview Monday evening with NBC 6 South Florida, the governor said there is going to be a need for a "forensics study" to determine the cause of the collapse. He said that while the state would provide support to the federal National Institute of Standards and Technology, a federal agency staffed by scientists and researchers that investigates building failures in extreme circumstances, he noted that the probe is "going to take a long time."
Asked if the governor, or any of his agencies, will be conducting a review of building inspection rules in each county, assembling state experts, or updating Florida inspection laws, the governor's communications office declined to comment.
Miami-Dade Mayor Daniella Levine Cava, however, is not waiting for state officials to decide to act.
On Tuesday, she announced she was moving forward with a plan to meet with subject matter experts "from engineering to legal to construction to development to soil to geology," she said.
They will "look closely at every possible angle on this issue related to building safety," she said. "They will advise me on issues related to the construction, chain of custody, requirements for reporting, condominium regulation, and more, so that my staff and I can develop a set of recommendations for changes that need to be made at all steps in the building process."
The goal, she added: "To ensure a tragedy like this will never, ever happen again."
Going Beyond Visual Inspections
Schwerdt, who has offices in South Florida, San Francisco and New York, said the state should require older buildings to be reinspected at least every 30 years, instead of every 40 years, and insist that visual inspections be augmented with inspections of a building's foundation and its subsurface levels, employing technological tools that weren't around when the 40-year reinspection rule was enacted in the 1970s..
"Evaluating the condition of a high-rise building requires testing the concrete, waterproofing and reinforcing steel," he said. "Visual evaluation is not enough to find deficiencies progressing inside the material, soil, and strength of the structure."
Current building inspection forms have no requirement to test the foundation, he said.
"They want you to check out the structural integrity of the building, but they don't make any specific requirements to test the foundation or to go deep underneath in any way whatsoever," said Wolf Schwerdt.
Questions have arisen about whether subsurface water contributed to the troubling amounts of concrete damage at Champlain Towers South.
Pools of standing water in the garage, deteriorating concrete slabs on the garage entrance and under the pool deck and the lack of proper drainage had caused "major structural damage, according to a 2018 engineering report done for the building's condominium association.
The report gave no indication that the building was at risk of collapse, but it detailed "abundant cracking" in concrete columns, beams and walls.
Two days before the building crumbled in the middle of the night, a pool contractor, hired to repair the exterior of the pool, noted a cracking concrete slab and severely corroded rebar under the pool. Several residents told the Miami Herald that standing water was a constant problem in the garage, even on days with no rain.
Former Champlain Towers maintenance manager, William Espinosa, told DeFede of CBS4, the Herald's news partner, that ocean saltwater would make its way into the underground garage so much that "pumps never could keep up with it."
Rising Sea Level Impact
Raul Schwerdt said that one of the functional deficiencies that could have contributed to the building's collapse is if the joint between the pool deck and the building had failed. A subsurface inspection of the columns could have identified if they had been weakened by the corrosion or if the underground piles had been eroded.
Florida buildings should be able to withstand those rising sea levels if built correctly, he added. "If the foundation has deep piles that go 30 feet under the sea that should hold the building forever no matter what happens — if a hurricane comes or the building is flooded."
But, "not every building is done the right way."
In addition to requiring inspections more frequently, the state should also require high rises to take into consideration the structures and the subsurface around a building, especially in vulnerable areas of the state, the engineers said.
But with more testing comes more cost and many building owners don't want to pay.
"It's up to the owners of the property to determine how much they are willing to spend on preventative maintenance and assets," Figueroa-Vallines said. "But if one unit owner has extensive cracking but the others don't see anything, are they going to want to do anything? That's the dilemma."
Wayne Pathman, a land-use attorney and member of Miami's Climate Resilience Committee, said in his experience, it's rare to find owners willing to go the extra mile to look underground.
Pathman said he once convinced a client buying hotels in Miami Beach to shell out extra for a ground-penetrating radar inspection of the site, a tough sell since the buildings had already passed their inspections. But the radar picked up millions of dollars of damage to the buildings' foundation, which the buyer was able to repair.
"He thanked me profusely afterward," he said.
(c)2021 Miami Herald Distributed by Tribune Content Agency, LLC.
