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MIAMI (AP) – Video released by a team of federal investigators shows more evidence of extensive corrosion and overcrowded concrete reinforcement at a Miami-area condominium that collapsed in June, killing 98 people.
The National Institute of Standards and Technology also announced Wednesday that it will conduct a five-part investigation into the collapse of the South Champlain Towers, which will be led by Judith Mitrani-Reiser. She is an engineer of Cuban origin who grew up in Miami.
“We are approaching this with an open mind and will be looking at any hypotheses that might explain what caused this collapse,” Mitrani-Reiser said. “Having an experienced team in various disciplines including structural and geotechnical engineering, materials, evidence gathering, modeling and more will ensure a thorough investigation. “
The video shows densely packed steel reinforcement in various sections of the building, as well as significant corrosion where a column met the building’s foundation.
“The corrosion at the bottom of this column is astronomical,” Dawn Lehman, professor of structural engineering at the University of Washington, said the Miami Herald. She said the amount of corrosion should have been evident and documented in the 40-year inspection underway when the building in Surfside, Fla., Collapsed on June 24..
“If there is that much corrosion, it should have been corrected,” she said.
The images show beams, walls and columns that appear to be overcrowded with steel reinforcement, suggesting potential weaknesses, she explained.
“There is no reason there is this kind of congestion in bars,” Lehman said.
The risk posed by “cluttered” vertical rebar in columns would have been even worse where the rebar overlapped, which is known as “lap splice” regions, said to the newspaper Abieyuwa Aghayere, an engineering researcher from Drexel University who also reviewed the video. .
Although it was already crowded with rebar, in the splice regions it would have been “even more crowded,” Aghayere told the Herald.
He said he was struck by the “powder snow” and the white concrete in the columns appearing in the recently released video. The stone-like aggregates used to reinforce the concrete during construction generally remain visible, but they were not in the images of the collapse site.
“The color white amazes me,” Aghayere told the newspaper. He added that instead of seeing aggregate mixed with concrete, “it’s just homogeneous,” which is likely an indication of salt water damage.
He said it’s impossible to tell from the pictures alone whether the concrete used in the original construction was weaker than the designs requested, or whether the apparent weakness was due to damage over time.
“It doesn’t look like normal concrete to me. What’s going on? ”Said Aghayere.
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