The Source Civil Engineering Magazine NIST will investigate Champlain Towers South collapse

NIST will investigate Champlain Towers South collapse

By Catherine A. Cardno, Ph.D.

The U.S. Department of Commerce’s National Institute of Standards and Technology, a federal research laboratory specializing in engineering and other technical areas, announced on June 30 that it would conduct a full technical investigation into the causes of the June 24 partial collapse of the Champlain Towers South condominium in Surfside, Florida.

The investigation could take years to complete and will seek to understand the technical cause of the building’s failure so the agency can, if it is deemed necessary, make recommendations for specific standard, code, and practice improvement in building design.

The Champlain Towers South condominium partially collapsed between 1:24 a.m. and 1:25 a.m. on June 24. The Washington Post reports that emergency responders were already en route to the site after a partial collapse of the swimming pool deck and surface level parking was reported via a 911 call at 1:19 a.m.

the partial collapse of the Champlain Towers South condominium
Champlain Towers South condominium partial collapse (Courtesy of NIST)

The town of Surfside has made public many of the tower’s building records, including a 2018 inspection report of the tower conducted by Frank P. Morabito, P.E., M.ASCE, the president of Morabito Consultants. Morabito provided the town with the report at 5:35 p.m. on the day of the collapse.

The report was provided to the condominium association in 2018 along with an estimate of the probable costs to make the extensive and necessary repairs that had been identified in the inspection, according to a statement on the firm’s website. Because the report was submitted to the town outside of the Miami-Dade County Code requirements, it is currently considered an unverified report despite having been submitted by Morabito.  

The NIST investigative team will include NIST staff and outside experts who will be deployed to Florida to examine the collapse site. The team will not interfere with currently ongoing search and rescue operations and will only enter the site when it has been determined safe to do so, according to the agency. NIST is working with government officials at the collapse site and will cooperate with all ongoing local, state, and federal investigations.

The NIST team will collect and study information about the building’s design, construction, modification, and maintenance as well as building materials and soil samples from the site.

a building element from the Champlain Towers South partial collapse is examined by four people in yellow vests, hard hats, and masks
NIST and U.S. Army Corps of Engineers staff members inspect a building element from the Champlain Towers South partial collapse in Surfside, Florida. (Courtesy of NIST)

The investigation is being launched by NIST under the National Construction Safety Team Act that was passed by Congress in 2002, the aim of which is to improve the safety and structural integrity of buildings. Under this act, the director is empowered to deploy expert teams after a building failure that either resulted in a substantial loss of life or posed a significant potential for doing so. (Currently James Olthoff, Ph.D., is performing the duties of the undersecretary of commerce for standards and technology and NIST director.)

The preliminary NIST team determined that the collapse met NCST Act criteria for full investigation under the Code of Federal Regulations: The partial collapse involved “a major building failure at significantly less than its design basis, during construction, or while in active use.”

The NCST act grants NIST the ability to collect and preserve evidence from the site of a failure, issue subpoenas, and hold hearings but not to conduct a criminal investigation.

NIST does not investigate all failures and disasters; this will be just the fifth investigation conducted and report issued by NIST under the NCST Act. The first four were the collapse of World Trade Center I, 2, and 7 after the terrorist attacks of Sept. 11, 2001; the 2003 Station nightclub fire in West Warwick, Rhode Island; the 2011 Joplin, Missouri, tornado; and the 2017 Hurricane Maria devastation in the northeastern Caribbean.

NIST seeks any videos or photos that might help the Champlain Towers South investigation and is encouraging the public to submit them via its dedicated data portal.

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11 COMMENTS

  1. Very damning 2018 inspection report–No way getting around that Condo Owner did NOT formally submit report as REQUIRED by Moiami-Dade County code.

  2. This report showed what they saw at the site. Was there a design and construction review? When there is a crack, spall, and large deflection, there must be a reason.

  3. The Real Cause of Champlain Towers South Collapse

    People all want to know why Champlain Towers South (a condo building) in Surfside, Florida collapsed at 1:30 AM on June 24, 2021. I think I have found the real cause of the collapse.

    The collapse has divided the building into two parts, the collapsed part and the still standing part. The collapsed part of the building is the eastern part of the building, and the still standing part of the building is the western part of the building. I also want to divide the foundation into two parts, the eastern part of the foundation and the western part of the foundation, the eastern part of the building was on the eastern part of the foundation and the western part of the building is still on the western part of the foundation.

    The problem was on the foundation, the western part of the foundation was harder, the eastern part of the foundation was softer, so the eastern part of the foundation had been sinking faster than the western part of the foundation, and finally the eastern part of the building collapsed.

    It’s very simple, the condo building is on a long small island running north-south, and obviously the building is on the eastern slope of the island. I think the original topography of the building site must have been a relatively steep slope, so the western part of the foundation is harder, and the eastern part of the foundation is softer.
    The eastern part of the foundation had been sinking faster than the western part of the foundation for all of these past 40 years.
    The western part of the building started to lift the western end of the eastern part of the building as soon as the eastern part of the foundation sank more than the western part of the foundation did, that lifting is actually a kind of shear force, that shear force had become bigger and bigger as the eastern part of the foundation sinking more and more than the western part of the foundation (year after year), that shear force finally (at 1:30 AM on June 24, 2021) became big enough to crack all the beams connecting the west part and east part of the building, so the western end of the eastern part of the building started to collapse, and then the entire eastern part of the building collapsed finally in seconds.

    I got information recently from CBS News that this building had been sinking at a rate of 2 mm a year, (I’m 100% sure that the eastern part of the foundation had been sinking faster than the western part of the foundation,) and that this building was constructed on reclaimed wetlands, (that means the designer might have ignored or been unable to check the original topography of the construction site— the topography of that slope.)

    So the ignorance of the original topography of the construction site is the real cause of the collapse.

    By the way, I also want to say:
    the west part of the building will not collapse soon, because it doesn’t need to lift the eastern part of the building any more, its burden has been reduced, it’s on the whole become safer than before, I think the rescuers needn’t to worry about that it will collapse at any time.
    As for its sister towers, Champlain Towers North and Champlain Towers East, if their foundations are in good condition, I think the residents can still live in their units.
    But we need to inspect other buildings’ foundation on the slopes of such small islands and shores.

    Wenbin Zhao

  4. I think I have found the real cause of that collapse.
    But I’m still keeping studying the process of the collapse, I have watched that collapse video for more than 100 times and carefully reviewed a lot of relevant photographs, I’m sure that the beams on the first floor (or basement) connecting the eastern part of the building and the western part of the building sheared off from the western end first, and then the second floor’s beams sheared off, the third, …… finally the twelfth floor’s beams were pulled off from the western part of the building. Please note, in such collapse when it goes to upper floors, the shear force is becoming weaker and the pull force is becoming stronger.
    But when the shearing off went to the fifth floor’s beams ( maybe fourth floor’s, I’m not sure, but it should be the middle floor’s beams), those sheared off beams impacted the columns on the eastern side heavily and broke off these columns, so the video shows that the middle of the eastern part of the building was dented first, the video can’t show the first floor’s beams shearing off, we can only watch the middle of the eastern part of the building was dented first.
    What the video shows and other photographs show are all in compliance with my mechanical analysis.
    Now I’m 99.9% sure that the real cause of that collapse is that the western part of the foundation is harder and the eastern part of the foundation was softer, and the designer ignore the original topography of the building site. If I’m able to go to the collapse site to look and review other data, I will be 100% sure about my conclusion.

    Wenbin Zhao

  5. We heard news nearly a week ago that the city of North Miami Beach ordered the evacuation of Crestview Towers Condo, I don’t know if this building is really safe or not, but I think the authorities should also think about if this building’s foundation has problem, if the northern part of the foundation is softer than the southern part of the foundation, if the northern part of the foundation has been sinking faster than the southern part of the foundation. Because this building is also very near to water, right on the southern bank of a river.
    Maybe Crestview Towers Condo has the same problem, the northern part of foundation is softer and sinking faster than the southern part of the foundation, just as that collapsed Champlain Towers South did.

  6. A recent photograph of the garage area showed the columns to be in very good shape but it also showed puddles of water, mostly around the bases of the columns. Could that indicate overpressure in the subgrade injecting water up through the joints? And could that overpressure have damaged or displaced the pile caps? Concrete has many wonderful properties but resistance to impact loading is not one of them. A lot of construction has taken place in the vicinity of the Champlain South since it was originally constructed. If the pile caps are damaged or displaced then the condition of the nearby buildings will be very much in question.

  7. Very good article, Catherine. The condo association shared the 2018 report with the Surfside Building Department, so everyone has retained counsel by now, I’m sure. The investigation will take years, but the litigation will take longer. Some interesting theories about differential settlement in the comments. I wouldn’t be too quick to assume a cause, as there may be several, each acting in a specific manner.

  8. Foundation engineering seems to be one tricky thing,in practice buildings are given a range within which to settle either uniformly or differentially, when it comes to the underlying soil it gets more trickier since soils can vary quite alot in profile evem over a small area ,yet most times the foundation is designed based on one site condition,you either design it as a fill or not a fill,either submerged or not submerged,but moisture movements are unpredictable at times and its nearly impossible to have accurate foundation soil details,even if we choose the worse case scenario.design continues through construction and structural integrity I believe should be monitored every 10years or less.

  9. According to the basic physics knowledge, this building must have been destroyed by a force, and since no one noticed this force, this force must have been becoming bigger and bigger quietly, and finally big enough to destroy this building. I think only uneven sinking of the foundation can produce such a kind of force, an imperceptible and bigger and bigger shear force to some beams of the building.

  10. Wenbin Zhao can solve Prominent Structural Engineer Allyn Kilsheimer’ puzzle about the Champlain Towers South collapse

    July 26, 2021
    Here is the conversation between Prominent Structural Engineer Allyn Kilsheimer and CBS News reporter Manuel Bojorquez on June 29, 2021

    Bojorquez: There is a high likelihood that this could’ve been a combination of things?
    Kilsheimer: It could’ve been a number things that alone wouldn’t have caused the problem, but together with a trigger, caused the problem.

    Allyn Kilsheimer is a structural engineer who has been hired by the town of Surfside to investigate the collapse. He has extensive experience investigating other disasters, like the 9/11 terrorist attack on the Pentagon and the Florida International University bridge collapse in 2018.
    One piece of the puzzle here, he says, is what a lobby attendant heard before the main collapse.

    Kilsheimer: He heard a muffled boom, and then X number of seconds later a much bigger boom, and then Y seconds after that a much bigger boom. So there were three booms. I think I understand the second one, I think I understand the third one, I don’t understand the first one.

    Please watch from 2:05 to 3:00 of this video at: https://www.cbsnews.com/video/florida-condo-collapse-audio-released-first-responders/?intcid=CNM-00-10abd1h#x

    According to my theory there should have been three booms, the first boom was the sound of the beams on the first floor or basement floor connecting the eastern part of the building and western part of the building sheared off from the western end impacting the floor, the second boom and the third boom are the sounds of the two collapse shown by the video. So I can solve the puzzle of Mr. Allyn Kilsheimer, and my analysis of the process of the collapse is completely in compliance with what that lobby attendant heard.
    Please recommend me to the investigation team, and let me convince them, I’m pretty sure they will accept my theory very soon.

    A contractor found the damages on the concrete in the pool equipment room two day before the collapse, I’m sure this is the last chance of the warning signs missed.

    And there were also warning signs in 2018 missed.

    And we also know that inspectors found damages on the concrete on the pool deck and in the underground garage in 1996 and called for repairs. I think those repairs couldn’t solve such problems, uneven foundation sinking caused problems.
    Please watch from 2:38 to 3:08 of this video at:
    https://abcnews.go.com/WNT/video/911-calls-released-surfside-condo-collapse-78851045

    According to the basic physics knowledge, this building must have been destroyed by a force, and since no one noticed this force, this force must have not had come suddenly, it must have had been becoming bigger and bigger quietly, and finally big enough to destroy this building. I think only uneven sinking of the foundation can produce such a kind of force, an imperceptible and bigger and bigger shear force to some beams of the building.

    When a concrete building is sinking, it can damage its satellite concrete structures, because these satellite concrete structures almost have no loads, they sink slower than the building and the foundation, so there must be shear forces on some of these satellite concrete structures’ beams, and these satellite structures are damaged first. These satellite concrete structures’ damages are exactly the first warning signs.

    These warning signs can really verify that the building had been sinking, and can also certify that my theory is correct.

    If the foundation of a concrete building is sinking evenly, it may not collapse. If the foundation of a concrete building is sinking unevenly, one part of the foundation is sinking faster than another part of the foundation, the sinking faster part will certainly collapse someday.

    If we find a concrete building’s satellite concrete structures are damaged, we should pay more careful attention, maybe it was caused by the sinking of the building’s foundation. If it was caused by uneven sinking of the foundation, the only thing we can do is to evacuate this building and demolish it, repairing the satellite concrete structure is a waste of money and will not stop the sinking of the foundation, and cannot prevent the building from collapsing.

    Wenbin Zhao

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