Champlain Towers NIST Update 4/11/25

[Reverse_Bias]

On Thursday, April 10, three members of the National Institute of Standards and Technology’s (NIST’s) National Construction Safety Team (NCST) investigating the June 2021 partial collapse of the Champlain Towers South building in Surfside, Florida, shared technical details of the investigation’s progress with members of the structural engineering professional community. This outreach will help ensure that the team’s findings and recommendations lead to improvements to codes, standards and practices that can prevent similar tragedies from occurring in the future.

Investigative lead Judith Mitrani-Reiser gave the technical presentation along with investigative co-lead Glenn Bell and Jim Harris, co-lead of the investigation’s Building and Code History Project. The presentation took place at Structures Congress 2025, an annual event of the Structural Engineering Institute of the American Society of Civil Engineers, held this year in Phoenix. While the three experts did not provide new findings, they did offer new technical details from the evidence analysis and testing that supported the preliminary findings NIST released in earlier public presentations.

https://www.nist.gov/news-events/ne...investigation-team-provides-update-structural

I found this presentation to be the most in depth of anything that NIST has released so far.
https://www.nist.gov/system/files/d...CTS_Special_Session_2025Apr10_FOR_RELEASE.pdf

 

[stcbus]

Thanks for the update. All interesting but hope more comes out soon. Crazy how much conversation here has died down about this.

 

[Roga50]

NIST released new video update...

NIST Releases Extensive Video Update on Champlain Towers South Investigation

The update reviews the investigation’s history, shares preliminary findings and highlights potential impacts

www.nist.gov

 

[Sym P. le]

Thanks for posting the update. At this point the updates are a bit of a dog and pony show but it's good that they are being thorough. They are still trying to assess if a column buckled under the tower as an initiating event ... but then they go back to the obvious planter/column 76 event. They seem oblivious to vehicle traffic maneuvering in the vicinity of that slab/column connection (such as the three ton Silverado) or broken rebar stubs on column 45/46 (across the lane from 76).

Previously posted here for further context.

I found the video/audio analysis interesting (about 29:30 into the video). Cueing up varied video perspectives to a common time reference can lead to interesting insights. They attempted to stabilize the ring camera analysis to the corner of column M8 (in the white box) but then apparently struggled to commit to it. I've made some adjustments for the following animated gif.



What jumped out for me was the apparent shift in camera perspective between the afternoon frame and the first collapse sequence frame (the foreground sofa, and table shift higher w.r.t. the background kitchen fixtures). This would suggest that the exterior wall already dropped, or in doing so, triggered the motion activated sequence. The credenza which the camera sits on can also get pushed around and tilted if it is tight against the wall and the feet aren't free to slide (here).



Also, including the video background.

 

[stcbus]

I know it’s obvious but it sucks we don’t know to be able to determine how accurate the analysis and modeling actually is or if it’s just generated nonsense. Such as the lab tests they did or figuring out the video timing (if it’s from ring, why do they not have the time already?).

Hoping some experts can chime in how you can determine how accurate the modeling is as I don’t understand any of it but it makes me curious if all of this is just over engineered scenarios that never happened or if they really have enough foundation to actually model what happened.