No numbers had changed since Friday morning when Miami-Dade County authorities raised the death toll to four and said 159 people were unaccounted for after the Champlain Towers South building tumbled early Thursday morning.
Only one deceased victim had been identified, 54-year-old Stacie Fang, whose son was pulled from the rubble alive by rescuers in dramatic video taken at the scene.
The high rise had been built in 1981 and was due for its first 40-year inspection under local regulations.
While an investigation into the collapse has barely begun, people have begun speculating what may have led to the tragedy.
A federal probe into the cause will likely be conducted by investigators from the National Institute of Standards and Technology, according to Glenn Corbett, a former member of the Federal Advisory Committee of the National Construction Safety Team and a fire protection engineer at John Jay College of Criminal Justice in New York.
He likened NIST to the National Transportation Safety Board, or NTSB, which handles investigations into plane and train crashes — except for buildings and infrastructure.
博士. Albert M. Bleakley, an expert on structural and geotechnical engineering at the Florida Institute of Technology, teaches courses that examine the Harbour Cay collapse in Cocoa Beach and the Hyatt Regency walkway collapse, which both occurred in 1981.
In those cases, collapses happened during or shortly after construction due to a combination of design and building errors.
“The Surfside collapse is very different in that the building was OK for around 40 years prior to the collapse,” 他说.
博士. Bleakley also outlined some possible causes, although he reiterated it’s too early to know for sure.
“Parts of the foundation may have settled at different rates, which can cause stresses in the structure,” 他说. “Concrete could have developed cracks over time which then slowly expanded, like a crack in a windshield.”
一个 2020 研究 into land and sea level rise conducted by Dr. Shimon Wdowinski at Florida International University had looked at the Champlain Towers site and determined it was sinking by between 1 和 3 mm a year in the 1990s. That could have sped up, slowed down in the ensuing decades, 他解释 本星期. Or it could have continued unevenly. 仍然, other cities see significantly larger subsidence without suffering building collapses, FIU noted in a new study.
“When we measure subsidence or when we see movement of the buildings, it’s worth checking why it happens,” Wdowinski said. “We cannot say what is the reason for that from the satellite images but we can say there was movement here.”