Where did the collapse of the Miami building begin?
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(CNN) -
After the Champlain Towers South building partially collapsed in Surfside, Florida last Thursday, questions remain about the building's structural integrity.
While the official cause of the collapse remains unknown, local and federal officials began efforts to try to determine why the building collapsed and also prevent similar events from occurring in neighboring buildings.
This is everything you need to know about the ongoing investigation:
Warnings before the collapse of the building
An April 2021 letter from the building's board chairman to residents said that some damage seen in a 2018 engineer's report, including to the garage, "had gotten significantly worse."
The 2018 report from an engineering company documented severe structural damage to the concrete slab below the pool deck and "cracks and chips" located in the parking lot.
Spalling is a term used to describe areas of concrete that have cracked or crumbled.
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The federal team advances the investigation
A group of federal officials from the National Institute of Standards and Technology is initiating a preliminary investigation of the collapsed building's materials, history, and applicable building codes at the time the building was constructed, the terrain surrounding the building, and many other factors, according to an agency official.
The six-person team includes scientists, structural engineers, and a geotechnical engineer.
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The collapse timeline
Allyn Kilsheimer, the structural engineer hired by the city of Surfside to investigate the reasons for the collapse, said his investigation could take a few months or more, although an exact time frame is unknown.
Kilsheimer said he has begun examining the building and will use a meticulous computer-aided removal process to try to identify the cause or causes.
"Unless it's an airplane or a bomb that you know caused all of this, sometimes it can't be reduced to just one cause," he explained.
"You don't know what you're going to end up with until you finish the whole study."
Possible clues to the collapse of the building
Although it is still unknown why the building partially collapsed, engineers who have reviewed the case say the investigation should focus on possible flaws near the base of the building.
According to Sinisa Kolar, a Miami-based engineering executive, forensic engineers will need to examine the columns on the ground floor.
In addition, Kolar hopes that the researchers will test concrete samples and check them against structural drawings.
Meanwhile, Joel Figueroa-Vallines, president of SEP Engineers, said he believes it is too early to draw conclusions, but also said he would focus an investigation on the foundations and "podium level" of the pool deck.
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A possibly deadly combination
In addition to structural problems and "40 years of exposure to salt, water, and salty air," the collapse may have been influenced by vibrations from construction work, heavy equipment on the roof, and water damage from the swimming pool. building, according to Mehrdad Sasani, professor of civil and environmental engineering at Northeastern University.
What's next
Miami-Dade County Mayor Daniella Levine Cava said she will meet with experts in subject areas such as engineering, geology, construction and legal fields to prevent this tragedy from happening again.
“They will advise me on issues related to building construction, chain of custody and reporting requirements, apartment regulation and more, so that my staff and I can develop a set of recommendations for changes that need to be made. in all steps of the building.
process to ensure that a tragedy like this never happens again, ”he said.
- CNN's Curt Devine, Hollie Silverman, Alyssa Kraus, Deanna Hackney, and Jamiel Lynch contributed to this article.
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