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A draft report on the 2021 partial collapse of the Champlain Towers South condominiums in Surfside, Fla., that killed nearly 100 people, is due in 2026 instead of 2025, federal investigators preparing the report say.
The US Department of Commerce’s National Institute of Standards and Technology (NIST) is pushing back the release date of its draft due to complications with interviews, access to public records, personnel and complex testing of slabs and columns, all of which have added six to seven. months until the report’s expected release, says Glenn Bell, associate principal investigator.
Bell and lead researcher Judith Mitrani-Reiser explained the delays and other issues in a Sept. 12 update to the National Construction Safety Team Advisory Committee, saying the revised schedule will complete the technical work by the end of May 2025 with the draft report. expected in spring 2026. NIST will determine the cause of the collapse and develop science-based recommendations to improve building safety.
In an earlier update in March, officials announced the conclusion that the condominium’s pool deck failed more than four minutes before the 12-story structure collapsed. At this update, the report was expected to be released in the fall of 2025.
The group has worked to minimize schedule impacts, but technical and programmatic challenges are extending the schedule, including a six- to seven-month increase in the expected duration of the slab column testing program, resulting from the complex nature of of the eight individual tests that each include the presence or absence of beams in the slab, different types of pillar support and rebar, and whether these pieces were corroded or not and to what degree. It is now expected to be completed by the end of January 2025.
“Our research is currently at an inflection point where we are prioritizing and wrapping up our technical activities so that we can move fully into synthesis and writing, and issue a report for public comment as soon as the science allows” , says Mitrani-Reiser.
One member of the committee’s geotechnical team went on extended leave before leaving the group, Bell adds, adding to the burden on the small remaining geotechnical team, which also took time to sort out through consulting and contractor options. The committee’s social science program has also experienced delays, with complications in finding key staff needed to access certain public records, draft interviews taking longer than expected, as well as a six-week pause in interviews around the third anniversary of the collapse.
“The interplay between the highly technical work of collapse modeling and the human evidence obtained in the interviews is really valuable and symbiotic,” says Glen, adding that information from an interview can lead to the reprioritization of subsequent interviews and subsequent technical work.
The delay did not sit well with Pablo Langesfled, whose daughter and son-in-law died in the sinking. In public statements, Langesfeld expressed his disappointment at the delay and inaction of the authorities.
“We don’t need more hypotheses, we need solid, concrete answers,” Langesfeld said. “We need answers now. We need answers today.”
Progress test
The researchers say progress is being made, including the completion of mechanical testing of physical tests, namely steel-reinforced concrete. The tests provide a detailed understanding of the strength and deformability of concrete and reinforcing steel collected from different parts of the structure.
Since March, the researchers have completed the wind load history study, defining the wind speeds and directions associated with the main wind demands affecting the structure over its 40-year lifespan, Mitrani says -Reiser In May, he adds, investigators worked with local police to move all the evidence into a single warehouse, which was then 3D scanned to allow virtual viewing of the evidence.
The research, so far, has considered more than 300 potential points of failure for 25 scenarios or failure hypotheses, Bell says. In March, the committee received tens of thousands more files from the civil litigation.
So far, he says, the committee has reviewed 60 gigabytes of data from about 11,000 files, completed 1,080 laboratory tests and examinations of concrete and rebar samples, 108 soil, groundwater, rock and foundation tests and conducted nearly 60 interviews with more than 90 in the works and 10 focus group sessions planned.
“We’ve learned an enormous amount that will inform our findings and recommendations,” he says. “However, this progress was achieved in the face of several large and unexpected challenges that we have overcome, but which have slowed some aspects of our research.”
The researchers drilled concrete cores from the building’s remains, preparing test samples that are then placed in a hydraulic press that squeezes the cores to their breaking points, finding the pressure needed to reach to their failure points, data that is then used in computer models.
Concrete and rebar tension tests are also being carried out, with cylindrical concrete cores pressed into the curved side, and engineers are recording the maximum load at failure. Samples of rebar are separated to find how quickly the bar is stretched before breaking as well as its breaking strength.
Other tests continue to determine the condition of the cement paste and aggregates that make up the structure’s concrete, as well as how quickly water can reach the steel embedded within, and the degradation of steel reinforcements at Champlain Towers.
