After Champlain Towers South partially collapsed in Surfside, Florida, last Thursday, questions continue to be asked about the building’s structural integrity.
While the official cause of the collapse remains unknown, local and federal officials have begun efforts to try to determine why the building partially collapsed, and also prevent similar events from happening in neighboring buildings.
Here’s everything you need to know about the investigation so far:
- Warnings before the collapse: An April 2021 letter from the condo's board president to residents said some damage observed in a 2018 engineer's report, including in the garage, "has gotten significantly worse." The 2018 report from an engineering firm documented severe structural damage to the concrete slab below the pool deck and "cracking and spalling" located in the parking garage. Spalling is a term used to describe areas of concrete that have cracked or crumbled.
- The federal team: A group of federal officials from the National Institute of Standards and Technology is launching a preliminary investigation of the collapsed building's materials, history and applicable building codes at the time the condo was built, the ground surrounding the building and numerous other factors, according to an agency official. The six-person team includes scientists, structural engineers and a geotechnical engineer.
- The timeline: Allyn Kilsheimer, the structural engineer hired by the town of Surfside to look into the reasons for the collapse, said his investigation could last a few months or longer, although an exact time frame is unknown. Kilsheimer said he has started examining the building and will use a meticulous, computer-assisted process of elimination to attempt to identify the cause or causes. "Unless it's a plane or a bomb that you know triggered this whole thing, sometimes you can't get it down to one cause," he explained. "You don't know what you're going to end up with until you finish the whole study."
- Potential leads: Although it still remains unknown why the building partially collapsed, engineers who have reviewed the case say the investigation should focus on potential failures near the building’s base. According to Sinisa Kolar, a Miami-based engineering executive, forensic engineers will need to examine the ground-floor columns. In addition, Kolar expects investigators will test samples of concrete and cross-reference that with structural drawings. Meanwhile, Joel Figueroa-Vallines, president of SEP Engineers, said he thinks it's too early to reach conclusions, but also said he would focus an investigation on the foundation and the "podium level" of the pool deck.
- A possibly deadly combination: In addition to structural problems and “40 years of exposure to salt, water and salt air,” the collapse may have been influenced by vibrations from construction work, heavy equipment on the roof and water damage from the building’s pool, according to Mehrdad Sasani, a professor of civil and environmental engineering at Northeastern University.
- What’s next: Miami-Dade County Mayor Daniella Levine Cava said she will be meeting with experts in subject areas like 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 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 to ensure a tragedy like this will never, ever happen again,” she said.
Read more about the rescue efforts and investigation here.
CNN's Curt Devine, Hollie Silverman, Alyssa Kraus, Deanna Hackney and Jamiel Lynch contributed reporting to this post.