As an aeronautical engineer by training and patent lawyer by trade, I can say that these are the best videos out there on the Surfside condo collapse. Josh's precise use of concepts and terminology is masterful. Thank you very much for awesome work.
@@BuildingIntegrity Want to get help with this: Joel 2 it is happening for free whether you know it or not you are behaving like locust plagues every on interested is in on this just by clicking it. It is having an intense effect designed by god to drain the swamp. They can't stop it. Make it official and ask the holy spirit to lead you, it's going to win whatever you do.
Who'd've thought the collapse of a building in Surfside, FL would lead me to watching YT videos about shear walls, columns, slabs, etc?! And, despite zero previous interest in anything related to this, am now actually thrilled to see a new 'BI' video. Come away from each feeling educated, so much so might even be able to share what I've learned with someone else and perhaps sound like I know what I'm talking about! LOL Thank you for the well-explained and detailed explanations, theories, etc. (Yes, sometimes difficult to see what's being drawn, especially when little contrast... such as red on dark image.)
Me too! I listen to these videos every night before bed and I've learned so much about something I've never had interest in previously. I appreciate that he doesn't speculate or make sensational comments because at the end of the day almost 100 ppl lost their lives and that needs to be remembered.
My husband (tradesman) and I here in New Zealand look forward to your videos, looking out for them each day and learning much about engineering, construction and forensic engineering. I am an adult education consultant, Masters qualified in education and eLearning, and also Masters qualified in Emergency Management, and have to say, your ability to articulate concepts in simplistic terms across a virtual medium, in an emergency context, is just stunning. Well done!
@@BuildingIntegrity great work. Have you been following Miami herald in terms of what’s going on with investigators . Missing documents etc? Def worth the read . This building may not have been followed to plan in some areas
@@shopiefraccount9782 Exactly. The concepts are quite simple and applicable in many other areas of mechanical designs too. The complexity happens when computing actual strength - how the different parts cooperates to take up loads. And how big each individual force will be. And how large movements will be. And how the forcements and movements are kept at a level where the individual elements can continue to maintain the required strength for the usable lifetime of the building. And how this is affected by actual materials, actual ways of placing/fixating the rebars etc. And then the little problem with how to design to handle weather, so rust, frost cracks etc will not destroy the building. On top of that comes all the other problems. Resistance to fire. Design of ventilation system to get required amount of air replacements per hour etc. In the end, it takes a huge amount of knowledge to go from "I understand the concepts" to be able to do actually design a building like this. Lots of mistakes possible, which is also why building codes keeps getting updated as more knowledge gets accumulated. Todays best practices should hopefully be must better than what was known at the time of design/construction of this building. And I'm pretty sure lots of new knowledge will come from the investigation of this tragedy.
As far as I am concerned these "Building Integrity" video posts are, by far, the best & most comprehensive ones I have seen. The information offered is easily understood and structured very professionally. Thanks again for your mindful & respectful presentations.
It's amazing just how thin that thing is and it provides a diaphragm. Actually, that thin sheet on your IKEA is a diaphragm and not a shear wall. The floors of the condo are diaphragms which carry the loads to the shear walls and bring those loads to the ground. Diaphragms go into shear though, and so the IKEA example is a good insight.
@@hebrews11vs5 it can be that thin cause it doesn't provide stability front to back, but in all directions left to right and top to bottom, and in that case the entire length or width of it are what absorbs the forces when you try to push it from the side
I’m not an engineer, but I’m a mechanic. I love learning how things work and what they are designed to do. This particular catastrophe has sparked an interest. This man explains it the best from all the channels I’ve researched. Thank you for the education.
I've been an engineering drafter for over 30 years. Those drawings are what I do. Everyone thinks that architects design buildings. I'd love to share these videos and talk about these things to friends and family but they can't get past, "Isn't that what architects do?" Two things: Who was the architect for this building? I suspect no one cares. Who was the engineer? I'm sure everyone cares. Final question, who was the engineer for the Sydney Opera House? There's hardly an Australian who knows the answer to that question but they all know who the architect was because it was taught at school and in the news media. I think there's a problem in the way that we're taught at school and by the news media. I enjoy the videos and it's why I watch. I've even had some engineering colleagues say, "Yeah, he's good!"
Frankly, I don’t know the opera house architect either, but the industry did this to themselves. The moment you separate look&feel from the integrity you’ll have the layman only see the facade.
Thank you so much! I have been recommending this channel as a very good way to get educated on structural engineering. No guessing, no conspiracies, but actual education. Thank you.
Thank you. We have no interest in making videos blaming this party or that... nor do I care for the folks playing the 911 tapes. It seems in poor taste. We are trying to take this tragic opportunity to hopefully avoid something like this in the future through education... see that *something* good comes out of it. Wish it didn't have to happen though.
And much more to appreciate too: NONE OF THE "THUMBNAIL" SENSATIONALISM or tabloid-style packaging so many channels use to draw eyeballs. And no emotionalism either. The deconstructions Josh presents and illustrates so beautifully with real-time structural drawings are all hierarchically layered. Starting from the macro level questions like "Did it start at the roof?" then progressively moving into more granular examinations methodically. This video answering audience questions is so respectful of his viewers fully engaged in learning , and Josh uses each as springboards to closer illustrations. Actually fascinating to me is seeing in the prior video Josh explicitly stating at the start "I'm not going to get into what sheer walls are because there are plenty of good explanations you can google for"... Only to come back here now and respond to viewers' lack of clarity on "what are they?" ...
Why am I so fascinated with this when it’s not a topic that previously I could’ve cared less about. It’s because you do such a great job teaching in a way we understand. Thank you for your research and hard work to clearly teach all these new followers who just want to understand the WHY and the HOW.
Youngsters interested in engineering will benefit from watching Josh. Nothing dull or boring, just clarity, great explanation, passion and making complex engineering understandable. Great content!
Shear webs prevent a rectangle from becoming a parallelogram. The load of an aircraft is supported by the top and bottom spars separated by the shear web. This building only had them in one direction if you don’t count the block walls in the apartments. Great video.
The only shear walls acting in the east-west direction are next to the elevators, so when the center portion fell the remaining east portion was no longer braced by the walls around the elevator. The short shear wall beside the stair would only act in the north-south direction, it would offer no strength in the east-west direction. The east part of the building could only rely on rigid frame action which it wasn't designed for, but the rigid frame action inherent in a cast in place building did give it temporary stability. After it started to lean a bit to the west then it would start failing all of the beam/column joints and that was the end of it.
I would find it unusual to find a lack of shear wall in the east-west direction in a hurricane prone area. Fundamentally, the moment shear counter-reaction would have been at the base of the structure (pool deck), potentially overstressing it if the concrete properties were compromised. Root cause was bad design day one, imho. Neglect accelerated the failure.
Virtually zero shear resistance in the East-West axis... how many OTHER highrises--from The Carolinas all the way 'round to the Mexican border (and beyond) are right now "getting away with it"??? =:O
Agreed! Same here, this is by far the best material i can ''use'' (because even i understand the rough physics behind it) to convince the more towards conspiracy-leaning part of my friends that stuff can actually happen for many different reasons. Sigh... Kudos to Josh and the Building Integrity team (i assume) for giving us these early insights.
I think what you have uncovered so far is excellent as for the shear walls the north side wall appears to have worked, the south shear wall doesn't appear to have been long enough as it only delayed the collapse and gave way from the pool side were the wall was missing. Secondly it appears that the pool deck collapse pulled and destabilise the three pillars of the centre part of the building if there was a shear wall in the parking garage separating the building from the pool deck, maybe the building would have survived long enough to evacuate the people. Just my thoughts from a naval engineer in the UK
I agree. I do not understand why both shear walls (a real one and a phony one) were designed to stiffen the building in one axis only. I would expect winds from the ocean in the unprotected direction. There should be a shear wall in another direction. The small shear wall (it "flipped" on the top of the rubble) was not only weak, but also too short (stiffened top floors only). So the engineer (probably forced by the investor, unfortunately both already dead) saved a lot of money. The disaster was caused by the fact that the pool deck (which collapsed 7 minutes before the building) was tied with the beam which connected three critical columns 16"X16" supporting the front of the building that collapsed first. We already know that the collapsed pool deck severely weakened the columns. Why in the critical area the building was supported by 16X16 columns, while in the "strong" part of the building the columns were 24X24? These columns should have been designed much stronger (if it not should have been a wall). The collapse of the pool deck should not have affected the strength of the building structure! I am just an MSME with no experience in building structures, but in my opinion the blame should be shared between the investor and his construction engineer, contractor (weak slabs) and the bldg. maintenance that allowed for rebar corrosion and spalling.
Seems to me that if shears walls are there to provide resistance due to wind loads, namely a hurricane in worst scenario, then there should be shear walls that could handle the load from the east, west, south or north.
@@adamgrabicki3987 Yes, hindsight is a cruel mistress, I am wondering when the reasons of the why and the who is to blame how many apartment buildings will be accessed much more critically by engineers and architects and either be declared unfit for habitation or straight out condemned due to them. I suspect it will be a significant number of buildings because this style was very popular in the late 70's and early 80's worldwide and many buildings maintenance has been poorly funded or ignored.
@@edzachary8657 just a quick note- even though hurricanes in general originate from the east, the actual direction they are coming from at landfall (for any one particular location) can be from any direction. There is a lot of wobble in the trajectory. Plus, the strongest winds a structure will encounter can also be from any direction, due to the circular rotation of the hurricane & eye. It can also be strongly influenced by the structures around you, and if those hold up (provide buffer) or fail at some point during the hurricane.
Hey, I just discovered your videos on the topic a few days ago. And I was particularly shocked by the extend of the concrete damage in the parking garage. The only time I have seen so much damage to a bottom slab like that was in industrial ruins that have been abandoned for 30+ years. Great job on the videos, you explain everything very well.
Thanks so much for this content. I work in marketing for a construction management firm, and have seen and heard these terms for years without really understanding them. Your clear and well-thought-through explanations and demonstrative graphics are great, and I believe are going to make me better at my job.
Thank you for recording this information. There is no way i would use it in "real life circumstances", but i have learned so much about general construction of buildings. When this building collapsed , all i could think of was how on earth did it just happen one night. Now i am learning why and how. This is a very interesting topic.
While you were discussing the sheer walls for some reason it came to mind views of 100 year old buildings that have the steel threaded rods that stick out beyond the end walls that have that star shape cap and big bolt over the end. A type of old style sheer wall. when you mentioned wood a good example is a wood railroad trestle bridge that has diagonal bracing in all directions. Great discussion by the way! I have stopped viewing anybody's posting their speculation videos on TH-cam about what happened. This is the best resource. I am surprised that city hall hasn't brought you in to explain it to them. Where I live we don't have those 40 or 50 year inspections. I wonder why we don't? Aren't all building structures trying to fall?
Yes they are. Everything ages and everything wants to return back to dust. That's part of entropy. Our job as structural engineers is to keep delaying that day.
Maybe a future topic, watching your discussion on piles, caps and foundations had me thinking "what do they do when they build a new building on an old site?" Remove the old piles, bore down and install new?
I am curious about this myself. I would assume that they would extract the old pilings, but I don't know. Something new for me to look up and learn about. Thanks!
You are a good teacher. I hope there are some young people watching who might start considering engineering getting an engineering education. For myself, I never get over that feeling of visualizing a thing (not buildings for me), calculating and drawing it, then seeing the actual thing once it is made. I use steel and other metals. Structural engineers 3D print in concrete.
Josh thank you so much for the videos that you do. I've watched all of them and I'm just fascinated with this process of forensic engineering. You do a fantastic job of teaching the basics and helping people to quickly and easily understand the physics of what we're looking at and what happened. Of course I know it's not the final word, but it's obvious that you know your stuff and you also are sharing information that might help TPTB to understand where to start looking at what happened. Keep up the great work, thanks again from North Carolina.
My whole family is engineers and to this day I don’t understand 90% of what they’re talking about, 20 mins listening to you is more beneficial than 36 years of others just jabbering nonsense lol, excellent job.
Well if you’re watching the news in the last many years you’ll notice that a great deal of what they say is mainly speculation, supposition and a very large steaming pile of self serving 💩. Sadly that about sums it up🥴
Lots of engineer minds have poor communication skills to laypersons. There is a layer of conversion that is necessary, just like a computer person who would talk to anyone in their computer language vs. converting their terms into layperson meanings and words. Happens all the time and those types have a hard time finding layperson words and meanings to make what they are thinking understandable to any non-engineer type.
As much as I watch these videos with the upmost interest, I realize a great many human tragedies lie behind this building collapse. Just now, I read a few obituaries over at the Miami Herald. That gives videos such as this one extra relevance. After all, you’re covering an incident with actual victims. We can at least hope for a thorough investigation with identifiable lessons to be learned.
Another channel trying to show what happened to this building showed what you highlighted in red, the stair well wall, as the roof of the tower that collapsed last. Im glad you're around to show us what's what or some people would be misleading others into oblivion.
Josh, thank you for your organized, clear, and carefully thought out presentations. You’re doing tremendous work to answer questions, without sensationalism.
We are so lucky that you are donating your time to help us understanding the fundamental aspects of the building (and construction in general) and how many contributing factors there are to it’s collapse. Your knowledge is outstanding and your explanations are the best I’ve ever seen. Thank you so much.
OUTSTANDING presentation. For those of us who are not engineers but who wish to understand the science behind this tragedy, your lessons are invaluable. Thank you.
Almost like the building was meant to collapsed. With all the technology we have today, the Champlain Towers South is a textbook case of what not to do. You, sir, is amazing. You have been providing great clarity and comfort in understanding the horrific tragedy. I’m learning so much of what to look for in a building. I keep thinking about the victims, especially the unit 412 facing the ocean that was last to collapse where that lady was on the phone with her husband explaining the pool deck but also finding a silver lining in it and these videos are helpful.
Presumably with the central portion gone, that east shear wall and weak-moment connection are then overloaded. No design would have anticpated the live loads and energy transfer paths rushing through the now unstable tower. From what you have discussed in these videos almost every element seems designed down to a mimimum which is fine if the elements are constructed well and remain static and unchallenged. Introduce weakness (corrosion, damage, defects, shock) and there is no resilience. The fact that 2/3 of the structure tore off leaving the western portion largely in place is incredible. A lot of energy and masss were moving across unplanned-for load paths.
It looks more and more that the building original design was "just good enough" with a minimum margin that the design could get away with (aka cheap). Whatever margin was there got eaten up with time. One has to wonder what was the trigger that started the collapse process.
@@milantrcka121 This is why I have a really bad feeling about Champlain Towers North, since they were built the same year. It sounds like they have done better maintenance over the years but maybe it's just a matter of time before it, too, cannot structurally stand. I know I wouldn't feel comfortable living there. The Towers East probably don't have to worry as much.
I have watched and rewatched these videos to better understand the variables relating to the collapse of this building. Josh has done an amazing job explaining technical details and concepts in a manner easily understood by lay people. Each video has been fascinating and informative and builds upon the prior videos. I find myself looking at the multistory buildings within my area and think how they may have been constructed. This is a fascinating subject! Thanks Josh!!
I hate that this tragedy happened but thank you for these great videos. Also where were you when I was taking physics in college?? This makes so much more sense and you really are a great teacher.
When i was taking engineering the instructor took us to a building in Oakland Park Florida and the walls were open i could see the cables of the sheer wall very cool science
For years I have looked at those long diagonal steel bars along the inside walls of metal buildings, and I could never wrap my head around what purpose they served. I gained a deeper understanding of physics/statics and dynamics today. Thank you. I feel like I could teach someone else this concept and they would understand it to the same degree I now do. That is the sign of great teaching. As long as you keep making videos, I will keep watching. Thank you so much for sharing your valuable time and energy and knowledge with the internet!
Without being critical of Josh (he is a much better structural engineer/instructor than I am) I think he should have said that much (but not all) of the bracing you see in modern buildings are acting in tension. (I .e. they look like big tie rods). I saw some calculations/draings for a mid-Victorian railway bridge once - and due to lack of computational resource it was designed as two separate structure one compression and the other tension.
It appears that the short e-w walls at the elevator shaft were not designed to be shear walls. (See foundation plan and the lack of any grade beams or added piles to resist the overturning forces) I believe that the design relied on the stucco covered un-reinforced masonry walls at the exterior of the building. One at the north-west corner of the building and one at the south wall. These would be infill masonry and are only shown on the architectural plans. Note that at the south wall this masonry in fill wall stops at the second floor. The wall doesn't continue to the first floor as there is provision for guest parking in this area. Instead there is a concrete moment frame (not detailed) at this location consisting of 5 24 inch square columns and a 30 by 42 inch deep beam. Its hard to believe that such a system would be approved but its the only explanation I have been able to come up with. (A retired structural engineer with 50 years experience)
Fascinating information. I will see concrete buildings in a new way from now on. Analyzing the destruction and seeing the structures has made for a fascinating way to catch my attention to learn. One good thing from this tragedy is if we are all a little smarter to ask to have the structural integrity of our buildings studied before it is too late.
Without a doubt the best video's on the web about the buildings collapse. Great work. Whenever I see the photo of the rubble pile however, my heart aches for the families who lost their loved ones in such a tragic manner.
Another excellent video, you’re explanations are fabulous, it’s hard to believe that the building had so little bracing considering its proximity to the ocean, and what there was of it was so poorly tied into the surrounding reo, we would be shot with a ball of our own shit, if we didn’t tie at least 300mm of the deck mats vertically into the walls, how that stairwell wall came away in one piece is just criminal.
Thank you for sharing your knowledge, staying on point and explaining every thing for the general public. Your examples clearly and concisely show what happened- in a logical manner.
One thing I’d be interested to know to relates to a claim I’ve seen in multiple eyewitness accounts; namely that the elevators and elevator doors had entirely collapsed, that portions of the main stairwell had collapsed, and that the rest of the stairwell had been torn away from one of the supporting walls (though apparently not to the extent where it was unable to support the combined weight of the people evacuating and the wreckage of the parts that had completely given way). What puzzles me here is that both of those sections were on the inner side of the shear wall, away from the wing of the building that collapsed. If the rebar was ripped right out of the remaining plate (i.e. the stairwell landings at each floor, which I’m guessing supported the weight of the staircase directly above) by the force of the collapsing plate on the other side of the wall, then that might have explained the state of the stairwell… Except that the stairwell _wasn’t actually connected to the collapsed part_ - there was nothing on the other side of it that _could_ have pulled that rebar out. The situation with the elevator shafts also seems strange; while I can definitely imagine the elevators themselves dropping if the forces from the collapse snapped the main cables, that doesn’t explain how the elevator doors & frames (on the inside of the shear wall, with no direct connection to the collapsed structure) also ended up destroyed. 14:30 In fact, after seeing the schematic here I suspect the back portion probably slopes away from the shear wall in the same way as the front portion that we can see; i.e. the vertical line we see in the video actually likely isn’t the rear end of the building, but an isolated “peak” of sorts near the middle, with both sides around it having already fallen away at this point. I doubt this has much importance in practice, however. The failure mode of this shear wall has very little bearing (if any at all) on the initiation of the collapse, and isn’t going to help us understand the set of factors that allowed it to occur and so how it might have been prevented. It could potentially have saved some lives if that wall had held out…but looking at how many people already died in the “only” partially destroyed units in the NW portion, I sadly don’t think it would’ve been very many. :-/
Thank you for taking your valuable time to explain these things to us non-engineers. I like knowing how things work, and finding out they fail is a good way to do that, but I don't have any formal education or training in this stuff. So thank you very much.
It seems to me that the shear walls are not as sturdy, or abundant, enough to support a building of this size, especially when you add all of the weight of occupancy and things like the giant planters (especially with the palm trees). I really appreciate you doing these videos. I find your approach extremely informative, and trust your methodology enough now that you are my go-to for questions. I look forward to seeing you work this into a theory for total building failure. I grew up in Florida, and unfortunately the old joke about contractors being paid off, in the 80s and 90s, especially, in South Florida, is well known by anyone in the building industry. I really hope that wasn’t the case here. The death toll of human and pet life is horrific and deeply saddens me. Anyway, best of luck to you! I’ll be watching along. You’re doing a phenomenal job.
Yea they're really not designed to "support" the building. They're designed to keep it from bending sideways in the wind. As he just explained in the video. Incidentally they also do resist collapse forces.
I think the lack of rebar (I know it's the wrong word technically, sort of like almost all drummers know Peart is "Peer-t" but all say "Pert," anyway)-- is going to be part of the fault. There's not much in the garage columns. That's what anyone can see in what got forced to the sides when it fell but not all the way.
My first thought of the east side of the building collapse, yes, the east shear wall was holding up the building, but it could not fully support a rotational moment about the vertical axis of the shear wall, So in the last few seconds, all the remaining standing floors rotated about the vertical axis of the shear wall (clockwise around the vector from the ground to sky), putting all the slab/column joints in high stress, thus they failed and collapsed in a pancake. But if you notice the east side of the building, the narrow 'nose' at the north east corner has rotated toward the piece of building that remained standing. The pancake of collapsed floors to me look like there was some clockwise angular momentum of the entire remaining structure as it came down.
Thanks, Mr. Josh. I am professionally involved with high rise buildings, and find your videos thorough, and educational. Finding time to study plans, and come up with theories is challenging while continuing your professional life. I'm appreciative of your knowledge, and forthright attitude. God bless.
Wood-framed (the vast majority of) homes here in California must have plywood shear wall sheathing in every exterior wall, as well as shear-resistant foundation/sill bolts, rafter/joust ties, etc. My old Victorian cottage doesn’t, and it shakes like crazy in every small earthquake. The building code has been strengthened to improve earthquake resistance after every major quake, especially the 1970 San Fernando, but older homes don’t have to be retrofitted. Unreinforced masonry construction hasn’t been allowed here for a long time. I understand that the lateral shear force for high winds, like hurricanes, are similar to that of earthquakes, so I suppose codes in the Southeast are similar.
Amazing dude! So many details that don't stand out to the untrained eye. I'd like to attend engineering courses taught by you. Let me know the tuition costs...
I love learning the basics. I believe that you guys care about what you do for a living. There are many other engineers that are making tons of videos on what happened to the Champlain towers and its just so confusing. I not only watch your Champlain towers videos, but I actually watched all of your videos from your day to day work and I've learned so much from you guys. I so appreciate your common sense approach in explaining building engineering. Thank you.
It would be really interesting to cover in a future video the following question: "what has (or hasn't) changed in today's construction techniques and building codes that makes a collapse like this less likely to occur" - it's something you hinted at in a previous video that this collapse may be partially attributable to the techniques and technologies available at the time it was built, and newer buildings may not be as susceptible to progressive collapses.
Concrete hasn't changed that much, but I would expect a lot more steel, particularly in a coastal area. I have seen a 3 storey building constructed with more rebar than that 12 storey one.
Something I noticed in the first collapse video is that section that collapsed with a slight delay appears to have experienced some visible oscillation during the initial collapse. Certainly the front section of it facing the camera anyway which supports the idea that section was likely seriously compromised internally there I'd have thought. Pretty sure reinforced concrete structures are not designed to repeatedly bend violently enough to be visible to the naked eye from that distance. I can't imagine this is good in the slightest for a reinforced concrete structure given concrete's propensity towards brittle rather than ductile deformation. Given the already appalling state of the maintenance of the building would not surprise me if that bit of oscillation was the final straw that guaranteed the inevitable failure of that portion.
It's amazing how many people are interested in this tragedy........ You are doing an amazing job with this series keeping us informed and teaching us along the way...... Thank you!😉
Josh, thank you for making a complex topic understandable to those of us who aren't experts like you! I've become fascinated by these videos, and have gone back to earlier videos to learn more. You're an excellent teacher.
I think the Washington Post had a graphic/article that said the west side of the building had extra reinforcement beyond the shear wall to help withstand hurricanes. Is that something you will find after looking further into the plans? Could you confirm or address this? My apologies, I’m not finding the article again. Thank you for the informative work! I took my toys apart as a kid to see how they work, so your videos have been fascinating to watch.
I will address this question in the video about the building design. It's taking longer to put together simply because there is a lot to look at. Some videos are easier for me to make while I'm still finishing that one up.
Love your videos. My dad is a welder. I’m a daddy’s girl and have helped him build anything from fences to houses to metal buildings. My daughter watches beauty gurus and I watch construction vids on YT. Haha! Both you & Jeff Ostroff should really consider teaching as you both have very good ways of explaining things so it’s easy for everyone to understand. I tried watching this one guys videos on the collapse but the minute he tried to “debunk” you and used that as a thumbnail, I was done. Keep up the good work!
thanks for the explanation. I'm looking at all the buildings is see now and wonder how vulnerable they are. I have new appreciation for building maintenance.
Anytime you have a deck supporting a wall that extends the entire height of the building, that wall should extend all the way to the base. And especially where the wall separates the indoor portion of the deck from the outdoor portion of the same deck. Couple that with a step grade difference on the deck and this postulation holds true even more.
What I’m curious about is the CDI contractors who said the concrete they were drilling into to place explosives felt nowhere near the spec the design required. I’m guessing they’ll be quite keenly looking into this, especially considering that drilling into concrete is what these guys do all day, every day.
It is strange that so expensive building was built from shitty materials, but still it had been standing 40 years. It was built on the edge of structural integrity.
As an aeronautical engineer by training and patent lawyer by trade, I can say that these are the best videos out there on the Surfside condo collapse. Josh's precise use of concepts and terminology is masterful. Thank you very much for awesome work.
Wow! Thank you!
@@BuildingIntegrity Want to get help with this:
Joel 2 it is happening for free whether you know it or not you are behaving like locust plagues every on interested is in on this just by clicking it.
It is having an intense effect designed by god to drain the swamp. They can't stop it. Make it official and ask the holy spirit to lead you, it's going to win whatever you do.
His is the best analysis, for sure!
@@michaelmcneil4168 ?
@@laurasalo6160 yes?
Who'd've thought the collapse of a building in Surfside, FL would lead me to watching YT videos about shear walls, columns, slabs, etc?! And, despite zero previous interest in anything related to this, am now actually thrilled to see a new 'BI' video. Come away from each feeling educated, so much so might even be able to share what I've learned with someone else and perhaps sound like I know what I'm talking about! LOL Thank you for the well-explained and detailed explanations, theories, etc. (Yes, sometimes difficult to see what's being drawn, especially when little contrast... such as red on dark image.)
Same. Exactly the same.
So agree. Fascinating stuff.
Ditto ! Watching shear loads before UFC Tonite ! Lol
Me too! I listen to these videos every night before bed and I've learned so much about something I've never had interest in previously. I appreciate that he doesn't speculate or make sensational comments because at the end of the day almost 100 ppl lost their lives and that needs to be remembered.
Exactly!!!
My husband (tradesman) and I here in New Zealand look forward to your videos, looking out for them each day and learning much about engineering, construction and forensic engineering. I am an adult education consultant, Masters qualified in education and eLearning, and also Masters qualified in Emergency Management, and have to say, your ability to articulate concepts in simplistic terms across a virtual medium, in an emergency context, is just stunning. Well done!
Sincerely... thanks! That means so much.
He makes highly technical and relevant issues understandable without throwing around judgements and blame.
Very much so!
Like some other "engineer" does???!!!! I can't stand that guy!
We're a good ways from that. The concrete itself has a story to tell.
He's very detailed and keeps things simple so non-engineers, such as myself can fully grasp what he's talking about.
@@pomonabill220 I unsubscribed from cat man’s channel. He got way too erratic, defensive, and annoying for me.
You guys are still the best on the Web for breaking this tragedy down from an engineering POV. Keep up the amazing work.
Thank you!
@@BuildingIntegrity great work. Have you been following Miami herald in terms of what’s going on with investigators . Missing documents etc? Def worth the read . This building may not have been followed to plan in some areas
@@BuildingIntegrity I feel like I could design a building by the end of this series! :P
@@Rx7man LOL. yes FEEL that way BUT won’t do it ... lol
@@shopiefraccount9782 Exactly. The concepts are quite simple and applicable in many other areas of mechanical designs too. The complexity happens when computing actual strength - how the different parts cooperates to take up loads. And how big each individual force will be. And how large movements will be. And how the forcements and movements are kept at a level where the individual elements can continue to maintain the required strength for the usable lifetime of the building. And how this is affected by actual materials, actual ways of placing/fixating the rebars etc.
And then the little problem with how to design to handle weather, so rust, frost cracks etc will not destroy the building.
On top of that comes all the other problems. Resistance to fire. Design of ventilation system to get required amount of air replacements per hour etc.
In the end, it takes a huge amount of knowledge to go from "I understand the concepts" to be able to do actually design a building like this. Lots of mistakes possible, which is also why building codes keeps getting updated as more knowledge gets accumulated. Todays best practices should hopefully be must better than what was known at the time of design/construction of this building.
And I'm pretty sure lots of new knowledge will come from the investigation of this tragedy.
As far as I am concerned these "Building Integrity" video posts are, by far, the best & most comprehensive ones I have seen. The information offered is easily understood and structured very professionally. Thanks again for your mindful & respectful presentations.
Thank you for watching.
I get it now.. that cardboard panel on the back of my Ikea furniture is the "shear wall" makes total sense. Thanks JP..
Exactly!
It's amazing just how thin that thing is and it provides a diaphragm. Actually, that thin sheet on your IKEA is a diaphragm and not a shear wall. The floors of the condo are diaphragms which carry the loads to the shear walls and bring those loads to the ground. Diaphragms go into shear though, and so the IKEA example is a good insight.
not if it doesn't go to the base.
Eureka!
@@hebrews11vs5 it can be that thin cause it doesn't provide stability front to back, but in all directions left to right and top to bottom, and in that case the entire length or width of it are what absorbs the forces when you try to push it from the side
I’m not an engineer, but I’m a mechanic. I love learning how things work and what they are designed to do. This particular catastrophe has sparked an interest. This man explains it the best from all the channels I’ve researched. Thank you for the education.
Thank you for watching!
You’d be a great engineering professor . You capture the listener . Thanks as always for your insight and analysis.
Thank you for the kind words!
@@BuildingIntegrity ❤️
Every time I watch one of your videos, it feels as if five minutes have gone by. You are an incredible teacher. Thank you.
Thanks!
I know! I was like I don’t really have time for a 20 min video right now and it gets to the end and I’m like wait what, that was not 20 mins.
I've been an engineering drafter for over 30 years. Those drawings are what I do. Everyone thinks that architects design buildings. I'd love to share these videos and talk about these things to friends and family but they can't get past, "Isn't that what architects do?" Two things: Who was the architect for this building? I suspect no one cares. Who was the engineer? I'm sure everyone cares. Final question, who was the engineer for the Sydney Opera House? There's hardly an Australian who knows the answer to that question but they all know who the architect was because it was taught at school and in the news media. I think there's a problem in the way that we're taught at school and by the news media. I enjoy the videos and it's why I watch. I've even had some engineering colleagues say, "Yeah, he's good!"
Architects draw up the pretty things, then they tell engineers, ok now, how do we hold it all together?
Frankly, I don’t know the opera house architect either, but the industry did this to themselves. The moment you separate look&feel from the integrity you’ll have the layman only see the facade.
Not only do you make this interesting, you do it in such a way that an ‘’average Joe’’ can understand it. Thanks for doing this.
You explain things very well and very clearly. I've learned a lot from watching and listening to your videos. Good job Sir!!!
He explains it better than anybody on youtube. I can tell he is an expert
Thank you so much! I have been recommending this channel as a very good way to get educated on structural engineering. No guessing, no conspiracies, but actual education. Thank you.
Thank you. We have no interest in making videos blaming this party or that... nor do I care for the folks playing the 911 tapes. It seems in poor taste. We are trying to take this tragic opportunity to hopefully avoid something like this in the future through education... see that *something* good comes out of it. Wish it didn't have to happen though.
And much more to appreciate too: NONE OF THE "THUMBNAIL" SENSATIONALISM or tabloid-style packaging so many channels use to draw eyeballs. And no emotionalism either. The deconstructions Josh presents and illustrates so beautifully with real-time structural drawings are all hierarchically layered. Starting from the macro level questions like "Did it start at the roof?" then progressively moving into more granular examinations methodically. This video answering audience questions is so respectful of his viewers fully engaged in learning , and Josh uses each as springboards to closer illustrations.
Actually fascinating to me is seeing in the prior video Josh explicitly stating at the start "I'm not going to get into what sheer walls are because there are plenty of good explanations you can google for"... Only to come back here now and respond to viewers' lack of clarity on "what are they?" ...
Never in my life did I think I would be so interested in building construction! Great job!!
I'm waiting for someone women to comment they decided to become structural engineers b/c of this guy. Lol
Why am I so fascinated with this when it’s not a topic that previously I could’ve cared less about. It’s because you do such a great job teaching in a way we understand. Thank you for your research and hard work to clearly teach all these new followers who just want to understand the WHY and the HOW.
Youngsters interested in engineering will benefit from watching Josh. Nothing dull or boring, just clarity, great explanation, passion and making complex engineering understandable. Great content!
I am not an engineer. Your videos are fascinating and highly educating. You are an excellent communicator and teacher. Thanks!
Thank you for doing this, can't wait for construction drawings video !
They are coming soon!
@@BuildingIntegrity See latest Miami Herald articles... re the drawings and storage unit etc.
Shear webs prevent a rectangle from becoming a parallelogram. The load of an aircraft is supported by the top and bottom spars separated by the shear web. This building only had them in one direction if you don’t count the block walls in the apartments. Great video.
It’s also a factor in convertible automobiles. If you’re ever driven one, you can feel the lack of rigidity immediately.
@@madmaxine12 Yeah, that's part of why decapitations are much more frequent in accidents involving them.
The only shear walls acting in the east-west direction are next to the elevators, so when the center portion fell the remaining east portion was no longer braced by the walls around the elevator. The short shear wall beside the stair would only act in the north-south direction, it would offer no strength in the east-west direction. The east part of the building could only rely on rigid frame action which it wasn't designed for, but the rigid frame action inherent in a cast in place building did give it temporary stability. After it started to lean a bit to the west then it would start failing all of the beam/column joints and that was the end of it.
Unleashed in the East
I would find it unusual to find a lack of shear wall in the east-west direction in a hurricane prone area. Fundamentally, the moment shear counter-reaction would have been at the base of the structure (pool deck), potentially overstressing it if the concrete properties were compromised. Root cause was bad design day one, imho. Neglect accelerated the failure.
Virtually zero shear resistance in the East-West axis... how many OTHER highrises--from The Carolinas all the way 'round to the Mexican border (and beyond) are right now "getting away with it"??? =:O
Excellent analysis. You are the only one I watch for info on this terrible incident. The official finding will take months I presume.
Agreed! Same here, this is by far the best material i can ''use'' (because even i understand the rough physics behind it) to convince the more towards conspiracy-leaning part of my friends that stuff can actually happen for many different reasons. Sigh...
Kudos to Josh and the Building Integrity team (i assume) for giving us these early insights.
I think what you have uncovered so far is excellent as for the shear walls the north side wall appears to have worked, the south shear wall doesn't appear to have been long enough as it only delayed the collapse and gave way from the pool side were the wall was missing.
Secondly it appears that the pool deck collapse pulled and destabilise the three pillars of the centre part of the building if there was a shear wall in the parking garage separating the building from the pool deck, maybe the building would have survived long enough to evacuate the people.
Just my thoughts from a naval engineer in the UK
I agree. I do not understand why both shear walls (a real one and a phony one) were designed to stiffen the building in one axis only. I would expect winds from the ocean in the unprotected direction. There should be a shear wall in another direction. The small shear wall (it "flipped" on the top of the rubble) was not only weak, but also too short (stiffened top floors only). So the engineer (probably forced by the investor, unfortunately both already dead) saved a lot of money. The disaster was caused by the fact that the pool deck (which collapsed 7 minutes before the building) was tied with the beam which connected three critical columns 16"X16" supporting the front of the building that collapsed first. We already know that the collapsed pool deck severely weakened the columns. Why in the critical area the building was supported by 16X16 columns, while in the "strong" part of the building the columns were 24X24? These columns should have been designed much stronger (if it not should have been a wall). The collapse of the pool deck should not have affected the strength of the building structure! I am just an MSME with no experience in building structures, but in my opinion the blame should be shared between the investor and his construction engineer, contractor (weak slabs) and the bldg. maintenance that allowed for rebar corrosion and spalling.
Seems to me that if shears walls are there to provide resistance due to wind loads, namely a hurricane in worst scenario, then there should be shear walls that could handle the load from the east, west, south or north.
@@smallgasengine805 I was thinking the same thing especially from the East where most of the hurricanes in this area of Florida are coming from
@@adamgrabicki3987 Yes, hindsight is a cruel mistress, I am wondering when the reasons of the why and the who is to blame how many apartment buildings will be accessed much more critically by engineers and architects and either be declared unfit for habitation or straight out condemned due to them.
I suspect it will be a significant number of buildings because this style was very popular in the late 70's and early 80's worldwide and many buildings maintenance has been poorly funded or ignored.
@@edzachary8657 just a quick note- even though hurricanes in general originate from the east, the actual direction they are coming from at landfall (for any one particular location) can be from any direction. There is a lot of wobble in the trajectory. Plus, the strongest winds a structure will encounter can also be from any direction, due to the circular rotation of the hurricane & eye. It can also be strongly influenced by the structures around you, and if those hold up (provide buffer) or fail at some point during the hurricane.
Hey, I just discovered your videos on the topic a few days ago. And I was particularly shocked by the extend of the concrete damage in the parking garage. The only time I have seen so much damage to a bottom slab like that was in industrial ruins that have been abandoned for 30+ years. Great job on the videos, you explain everything very well.
The way you are able to explain this stuff to an audience with no SE background is Brilliant!!
JP paid attention in school.
Really impressed with how thorough Josh is. Really covering everything through and through. Excellent job and video
Hey don’t forget K bracing, haunch and other goodies. It feels good being back in Engineering classroom.
Thanks so much for this content. I work in marketing for a construction management firm, and have seen and heard these terms for years without really understanding them. Your clear and well-thought-through explanations and demonstrative graphics are great, and I believe are going to make me better at my job.
This strikes right at the heart of what I'm trying to do. Means a lot to hear this. Thanks!
Thank you for recording this information. There is no way i would use it in "real life circumstances", but i have learned so much about general construction of buildings. When this building collapsed , all i could think of was how on earth did it just happen one night. Now i am learning why and how. This is a very interesting topic.
While you were discussing the sheer walls for some reason it came to mind views of 100 year old buildings that have the steel threaded rods that stick out beyond the end walls that have that star shape cap and big bolt over the end. A type of old style sheer wall. when you mentioned wood a good example is a wood railroad trestle bridge that has diagonal bracing in all directions.
Great discussion by the way! I have stopped viewing anybody's posting their speculation videos on TH-cam about what happened. This is the best resource. I am surprised that city hall hasn't brought you in to explain it to them. Where I live we don't have those 40 or 50 year inspections. I wonder why we don't? Aren't all building structures trying to fall?
Yes they are. Everything ages and everything wants to return back to dust. That's part of entropy. Our job as structural engineers is to keep delaying that day.
The bridge is a truss which uses struts for the shear and other loads, not a skin or membrane.
I have to tell you Josh, some of this is over my head. But most of it is perfectly understandable. Thank you.
Maybe a future topic, watching your discussion on piles, caps and foundations had me thinking "what do they do when they build a new building on an old site?" Remove the old piles, bore down and install new?
I am curious about this myself. I would assume that they would extract the old pilings, but I don't know. Something new for me to look up and learn about. Thanks!
You are a good teacher. I hope there are some young people watching who might start considering engineering getting an engineering education.
For myself, I never get over that feeling of visualizing a thing (not buildings for me), calculating and drawing it, then seeing the actual thing once it is made. I use steel and other metals. Structural engineers 3D print in concrete.
I was hoping to hear a woman comment that she went to college for it on account of this guy. Lol
Josh thank you so much for the videos that you do. I've watched all of them and I'm just fascinated with this process of forensic engineering. You do a fantastic job of teaching the basics and helping people to quickly and easily understand the physics of what we're looking at and what happened.
Of course I know it's not the final word, but it's obvious that you know your stuff and you also are sharing information that might help TPTB to understand where to start looking at what happened. Keep up the great work, thanks again from North Carolina.
As an engineer I appreciate your indepth analysis!
Facts, engineering, and not speculation!
Just wanted to say, you do a really good job explaining everything! Good job!
Excellent teacher.
Thanks!
Yes indeed he is. Please keep them coming.
My whole family is engineers and to this day I don’t understand 90% of what they’re talking about, 20 mins listening to you is more beneficial than 36 years of others just jabbering nonsense lol, excellent job.
Hahaha...This is my situation also. Thank you for your help in understanding this catastrophe.
😂😂
Well if you’re watching the news in the last many years you’ll notice that a great deal of what they say is mainly speculation, supposition and a very large steaming pile of self serving 💩. Sadly that about sums it up🥴
Lots of engineer minds have poor communication skills to laypersons. There is a layer of conversion that is necessary, just like a computer person who would talk to anyone in their computer language vs. converting their terms into layperson meanings and words. Happens all the time and those types have a hard time finding layperson words and meanings to make what they are thinking understandable to any non-engineer type.
@@drizler I've noticed that. Most stories seem to be, "This may have happened. We'll update this story when we find out if it actually happened."
You make it so easy to understand, it seems like just common sense. THANK YOU
I wish my engineering professors had been as thorough as you are in explaining concepts. I may have made it past my junior year. Lol. Thanks much.
Your analysis is top-notch, far better than the many others who are maxing videos.
Thank you!
As much as I watch these videos with the upmost interest, I realize a great many human tragedies lie behind this building collapse. Just now, I read a few obituaries over at the Miami Herald. That gives videos such as this one extra relevance. After all, you’re covering an incident with actual victims. We can at least hope for a thorough investigation with identifiable lessons to be learned.
You always make complicated subjects so much more understandable! Thank you!
Thank you!
Great video! Always looking forward to the next one!
Thank you!
Another channel trying to show what happened to this building showed what you highlighted in red, the stair well wall, as the roof of the tower that collapsed last. Im glad you're around to show us what's what or some people would be misleading others into oblivion.
Lol, How did that other guy explain the stairwell remnants on the "roof"?
@@JCrook1028
He said what BI said was the stairwell wall, he said was the Roof to the stairwell area.
Great work, Josh. Thanks for continuing this series. I'm anxious to see the next episodes.
Josh, thank you for your organized, clear, and carefully thought out presentations. You’re doing tremendous work to answer questions, without sensationalism.
Thank you!
Thank you. Nice to get an in-depth look at how those buildings are put together and how force is offset
Great video! Every time I view one of your videos I see more things that are questionable. Great job!
We are so lucky that you are donating your time to help us understanding the fundamental aspects of the building
(and construction in general) and how many contributing factors there are to it’s collapse. Your knowledge is outstanding and your explanations are the best I’ve ever seen. Thank you so much.
Great work, this has to be the most informative set of videos being done on this. Thanks for what you're doing!
OUTSTANDING presentation.
For those of us who are not engineers but who wish to understand the science behind this tragedy, your lessons are invaluable.
Thank you.
Almost like the building was meant to collapsed. With all the technology we have today, the Champlain Towers South is a textbook case of what not to do.
You, sir, is amazing. You have been providing great clarity and comfort in understanding the horrific tragedy. I’m learning so much of what to look for in a building. I keep thinking about the victims, especially the unit 412 facing the ocean that was last to collapse where that lady was on the phone with her husband explaining the pool deck but also finding a silver lining in it and these videos are helpful.
Well engineered to fall in it's own footplan. Imaging the toll if it had fallen on it's neighbor.
Thank you for taking the Time to do this. Learning so much.
Presumably with the central portion gone, that east shear wall and weak-moment connection are then overloaded. No design would have anticpated the live loads and energy transfer paths rushing through the now unstable tower. From what you have discussed in these videos almost every element seems designed down to a mimimum which is fine if the elements are constructed well and remain static and unchallenged. Introduce weakness (corrosion, damage, defects, shock) and there is no resilience. The fact that 2/3 of the structure tore off leaving the western portion largely in place is incredible. A lot of energy and masss were moving across unplanned-for load paths.
It looks more and more that the building original design was "just good enough" with a minimum margin that the design could get away with (aka cheap). Whatever margin was there got eaten up with time. One has to wonder what was the trigger that started the collapse process.
@@milantrcka121 This is why I have a really bad feeling about Champlain Towers North, since they were built the same year. It sounds like they have done better maintenance over the years but maybe it's just a matter of time before it, too, cannot structurally stand. I know I wouldn't feel comfortable living there. The Towers East probably don't have to worry as much.
I have watched and rewatched these videos to better understand the variables relating to the collapse of this building. Josh has done an amazing job explaining technical details and concepts in a manner easily understood by lay people. Each video has been fascinating and informative and builds upon the prior videos.
I find myself looking at the multistory buildings within my area and think how they may have been constructed. This is a fascinating subject! Thanks Josh!!
I hate that this tragedy happened but thank you for these great videos.
Also where were you when I was taking physics in college?? This makes so much more sense and you really are a great teacher.
Hey man keep digging and stay on top of it that way people like me who don't watch the news still can keep informed on the proper information
As usual a very good comprehensive thorough video explaining this tragedy.
When i was taking engineering the instructor took us to a building in Oakland Park Florida and the walls were open i could see the cables of the sheer wall very cool science
For years I have looked at those long diagonal steel bars along the inside walls of metal buildings, and I could never wrap my head around what purpose they served. I gained a deeper understanding of physics/statics and dynamics today. Thank you.
I feel like I could teach someone else this concept and they would understand it to the same degree I now do.
That is the sign of great teaching.
As long as you keep making videos, I will keep watching. Thank you so much for sharing your valuable time and energy and knowledge with the internet!
Without being critical of Josh (he is a much better structural engineer/instructor than I am) I think he should have said that much (but not all) of the bracing you see in modern buildings are acting in tension. (I .e. they look like big tie rods).
I saw some calculations/draings for a mid-Victorian railway bridge once - and due to lack of computational resource it was designed as two separate structure one compression and the other tension.
Eagerly check for your you tubes every day. Answers to this collapse have to be determined. Your analysis is key.
Thank you!
It appears that the short e-w walls at the elevator shaft were not designed to be shear walls. (See foundation plan and the lack of any grade beams or added piles to resist the overturning forces) I believe that the design relied on the stucco covered un-reinforced masonry walls at the exterior of the building. One at the north-west corner of the building and one at the south wall. These would be infill masonry and are only shown on the architectural plans. Note that at the south wall this masonry in fill wall stops at the second floor. The wall doesn't continue to the first floor as there is provision for guest parking in this area. Instead there is a concrete moment frame (not detailed) at this location consisting of 5 24 inch square columns and a 30 by 42 inch deep beam. Its hard to believe that such a system would be approved but its the only explanation I have been able to come up with. (A retired structural engineer with 50 years experience)
probably correct as wind loading was not emphasized in 1980 .They used the dead load of the building to resist.
This guy is becoming a legend.
Fascinating information. I will see concrete buildings in a new way from now on. Analyzing the destruction and seeing the structures has made for a fascinating way to catch my attention to learn. One good thing from this tragedy is if we are all a little smarter to ask to have the structural integrity of our buildings studied before it is too late.
Without a doubt the best video's on the web about the buildings collapse. Great work.
Whenever I see the photo of the rubble pile however, my heart aches for the families who lost their loved ones in such a tragic manner.
Another excellent video, you’re explanations are fabulous, it’s hard to believe that the building had so little bracing considering its proximity to the ocean, and what there was of it was so poorly tied into the surrounding reo, we would be shot with a ball of our own shit, if we didn’t tie at least 300mm of the deck mats vertically into the walls, how that stairwell wall came away in one piece is just criminal.
Poorly built American infrastructure...save money by cutting corners and doing the bare minimum
@@billiamc1969 Profit above everything else.
This movie was far better than I expected and it had its suspenseful moments, so from the 1940s to 2021, nice job of a movie.
You bot accounts are so weird.
Thank you for sharing your knowledge, staying on point and explaining every thing for the general public. Your examples clearly and concisely show what happened- in a logical manner.
One thing I’d be interested to know to relates to a claim I’ve seen in multiple eyewitness accounts; namely that the elevators and elevator doors had entirely collapsed, that portions of the main stairwell had collapsed, and that the rest of the stairwell had been torn away from one of the supporting walls (though apparently not to the extent where it was unable to support the combined weight of the people evacuating and the wreckage of the parts that had completely given way).
What puzzles me here is that both of those sections were on the inner side of the shear wall, away from the wing of the building that collapsed.
If the rebar was ripped right out of the remaining plate (i.e. the stairwell landings at each floor, which I’m guessing supported the weight of the staircase directly above) by the force of the collapsing plate on the other side of the wall, then that might have explained the state of the stairwell… Except that the stairwell _wasn’t actually connected to the collapsed part_ - there was nothing on the other side of it that _could_ have pulled that rebar out.
The situation with the elevator shafts also seems strange; while I can definitely imagine the elevators themselves dropping if the forces from the collapse snapped the main cables, that doesn’t explain how the elevator doors & frames (on the inside of the shear wall, with no direct connection to the collapsed structure) also ended up destroyed.
14:30 In fact, after seeing the schematic here I suspect the back portion probably slopes away from the shear wall in the same way as the front portion that we can see; i.e. the vertical line we see in the video actually likely isn’t the rear end of the building, but an isolated “peak” of sorts near the middle, with both sides around it having already fallen away at this point.
I doubt this has much importance in practice, however. The failure mode of this shear wall has very little bearing (if any at all) on the initiation of the collapse, and isn’t going to help us understand the set of factors that allowed it to occur and so how it might have been prevented. It could potentially have saved some lives if that wall had held out…but looking at how many people already died in the “only” partially destroyed units in the NW portion, I sadly don’t think it would’ve been very many. :-/
The investigators should hire Josh to interview the eye wittnesses.
Thank you for taking your valuable time to explain these things to us non-engineers. I like knowing how things work, and finding out they fail is a good way to do that, but I don't have any formal education or training in this stuff. So thank you very much.
It seems to me that the shear walls are not as sturdy, or abundant, enough to support a building of this size, especially when you add all of the weight of occupancy and things like the giant planters (especially with the palm trees).
I really appreciate you doing these videos. I find your approach extremely informative, and trust your methodology enough now that you are my go-to for questions. I look forward to seeing you work this into a theory for total building failure. I grew up in Florida, and unfortunately the old joke about contractors being paid off, in the 80s and 90s, especially, in South Florida, is well known by anyone in the building industry. I really hope that wasn’t the case here. The death toll of human and pet life is horrific and deeply saddens me.
Anyway, best of luck to you! I’ll be watching along. You’re doing a phenomenal job.
Yea they're really not designed to "support" the building. They're designed to keep it from bending sideways in the wind. As he just explained in the video. Incidentally they also do resist collapse forces.
I think the lack of rebar (I know it's the wrong word technically, sort of like almost all drummers know Peart is "Peer-t" but all say "Pert," anyway)-- is going to be part of the fault. There's not much in the garage columns. That's what anyone can see in what got forced to the sides when it fell but not all the way.
My first thought of the east side of the building collapse, yes, the east shear wall was holding up the building, but it could not fully support a rotational moment about the vertical axis of the shear wall, So in the last few seconds, all the remaining standing floors rotated about the vertical axis of the shear wall (clockwise around the vector from the ground to sky), putting all the slab/column joints in high stress, thus they failed and collapsed in a pancake. But if you notice the east side of the building, the narrow 'nose' at the north east corner has rotated toward the piece of building that remained standing. The pancake of collapsed floors to me look like there was some clockwise angular momentum of the entire remaining structure as it came down.
I agree. I also think Josh's drawing is slightly incorrect -- more of the front (south) face of the east section had already fallen.
That’s how I saw it too
Thank you for such a good video and making things so clear. I had taken a literal meaning of a shear wall but now know better.
Thanks, Mr. Josh. I am professionally involved with high rise buildings, and find your videos thorough, and educational. Finding time to study plans, and come up with theories is challenging while continuing your professional life. I'm appreciative of your knowledge, and forthright attitude. God bless.
Wood-framed (the vast majority of) homes here in California must have plywood shear wall sheathing in every exterior wall, as well as shear-resistant foundation/sill bolts, rafter/joust ties, etc. My old Victorian cottage doesn’t, and it shakes like crazy in every small earthquake. The building code has been strengthened to improve earthquake resistance after every major quake, especially the 1970 San Fernando, but older homes don’t have to be retrofitted. Unreinforced masonry construction hasn’t been allowed here for a long time. I understand that the lateral shear force for high winds, like hurricanes, are similar to that of earthquakes, so I suppose codes in the Southeast are similar.
2:52 that makes sense what we saw in the ring cam from the living room. the stretch
22.5 ft is coincidentally also the height of catenary lines above Amtrak trains.
Interesting!
New video by this guy? Hell yeah I’m in this guy rocks
Thank you for helping us understand.
Amazing dude! So many details that don't stand out to the untrained eye. I'd like to attend engineering courses taught by you. Let me know the tuition costs...
Another exceptional, informative, and educational presentation made with/from intelligence and experience without hubris. Thank you!!
I love learning the basics. I believe that you guys care about what you do for a living. There are many other engineers that are making tons of videos on what happened to the Champlain towers and its just so confusing. I not only watch your Champlain towers videos, but I actually watched all of your videos from your day to day work and I've learned so much from you guys. I so appreciate your common sense approach in explaining building engineering. Thank you.
It would be really interesting to cover in a future video the following question: "what has (or hasn't) changed in today's construction techniques and building codes that makes a collapse like this less likely to occur" - it's something you hinted at in a previous video that this collapse may be partially attributable to the techniques and technologies available at the time it was built, and newer buildings may not be as susceptible to progressive collapses.
Concrete hasn't changed that much, but I would expect a lot more steel, particularly in a coastal area. I have seen a 3 storey building constructed with more rebar than that 12 storey one.
Something I noticed in the first collapse video is that section that collapsed with a slight delay appears to have experienced some visible oscillation during the initial collapse. Certainly the front section of it facing the camera anyway which supports the idea that section was likely seriously compromised internally there I'd have thought. Pretty sure reinforced concrete structures are not designed to repeatedly bend violently enough to be visible to the naked eye from that distance. I can't imagine this is good in the slightest for a reinforced concrete structure given concrete's propensity towards brittle rather than ductile deformation. Given the already appalling state of the maintenance of the building would not surprise me if that bit of oscillation was the final straw that guaranteed the inevitable failure of that portion.
I can't get enough of your videos and I've watched them all. You need to make some more please. lol
It's amazing how many people are interested in this tragedy........
You are doing an amazing job with this series keeping us informed and teaching us along the way......
Thank you!😉
Thank you for all of this educational content!
No, thank YOU for watching!
Josh, thank you for making a complex topic understandable to those of us who aren't experts like you! I've become fascinated by these videos, and have gone back to earlier videos to learn more. You're an excellent teacher.
The east end looks like it's twisting as it comes down, pivoting on the shear wall.
Thank you Professor another fabulous learning experience
I think the Washington Post had a graphic/article that said the west side of the building had extra reinforcement beyond the shear wall to help withstand hurricanes. Is that something you will find after looking further into the plans? Could you confirm or address this? My apologies, I’m not finding the article again. Thank you for the informative work! I took my toys apart as a kid to see how they work, so your videos have been fascinating to watch.
I will address this question in the video about the building design. It's taking longer to put together simply because there is a lot to look at. Some videos are easier for me to make while I'm still finishing that one up.
Josh is giving out free knowledge he paid to get thanks. Nice haircut also
Love your videos. My dad is a welder. I’m a daddy’s girl and have helped him build anything from fences to houses to metal buildings. My daughter watches beauty gurus and I watch construction vids on YT. Haha! Both you & Jeff Ostroff should really consider teaching as you both have very good ways of explaining things so it’s easy for everyone to understand. I tried watching this one guys videos on the collapse but the minute he tried to “debunk” you and used that as a thumbnail, I was done. Keep up the good work!
Excellent info, thank you for helping us to understand the failures.
Thank you for watching!
thanks for the explanation. I'm looking at all the buildings is see now and wonder how vulnerable they are. I have new appreciation for building maintenance.
Awesome way to start my weekend! Thanks for sharing.
Cheers.
Anytime you have a deck supporting a wall that extends the entire height of the building, that wall should extend all the way to the base. And especially where the wall separates the indoor portion of the deck from the outdoor portion of the same deck. Couple that with a step grade difference on the deck and this postulation holds true even more.
What I’m curious about is the CDI contractors who said the concrete they were drilling into to place explosives felt nowhere near the spec the design required. I’m guessing they’ll be quite keenly looking into this, especially considering that drilling into concrete is what these guys do all day, every day.
It is strange that so expensive building was built from shitty materials, but still it had been standing 40 years. It was built on the edge of structural integrity.
@@alexanderbelov6892 That's what happens when you have the mob as the contractor... my guess.
@@alexanderbelov6892 if anything, that goes to show how good flat slab stuff is, if it can take that much punishment for so long.