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Florida Building Collapse Discussion

I have had a building partially collapse….actually we lost 2 sections of the roof, then a few days more, when all the “Brazilian Engineers” were inspecting, one guy yelled from atop a 36 ft scaffolding snd said, It’s gonna fall. And it did.

I was the project manager to get a new roof….and learned a lot about concrete construction. I was also the Engineering Manager for a “bomb proof” building in .Sanford….so this was fascinating.

I did find a summary, but the paywall from the Anchorage Daily News will not copy.

The gist was this….maybe 6 causes or a variety or interdependent issues.

The failure was almost a perfect implosion demolition job. If you look at the video, you might not pick up the subtleties of that…here is a graphic that I found. I did not realize the full gravity nor the complete failure.

Before I go into my “thoughts”, there was one factoid shared yesterday that might change the theories. A lady on the fourth floor called her husband and said that the building was shaking and that the pool, which was lighted and visible from her balcony had “disappeared” of totally sunk. Then the line went dead….

The two main theories were that the “foundation” slab had failed. The comments about the improper drainage and the impact on the slab were discussed in the Engineer’s report in 2018. That also discussed the deteriorating columns of the underground parking garage. I THINK it was underground and you drove down a ramp to park and there were units on the ground level or first floor.

There were also reports of water (salt or brackish or fresh?) in the basement or on the floor of the parking garage….and that was an observation recently made.

Back to the two main theories,…

Foundation failure. Corrosion, improper construction, water penetration or drainage (surface or seawater pressure?)….the list goes on. What is not clear to me is whether the foundation slab was a conventional design….X inches of Y PSI concrete with a rebar matrix. OR was it a post tensioned slab. That means that cables….up to maybe 1-1 1/2 “ diameter were embedded in the slab and as the slab cured, the cables were connected to eye bolts and the bolts were torqued and the slab was in a state of compression. My building in Sanford had a large section, cordoned off by two tunnels with air locks on each end. The floor, with a complete basement full of vacuum pumps was stressed…..as was the walls and the roof. There were two large Jet Engines or Joy Blowers that could inflate or deflate the building to maintain barometric pressure…within 5/100 of an inch. We had to maintain temperature, humidity and pressure in order to flow test as well as adjust the main metering rod (it was tapered and centered in the main jet) of a single barrel carburetor. We did that through the worst hurricanes. The air locks were for safety. One individual decided to “exit” using an emergency door for a smoke break. The building was being pressurized or inflated. He was literally blown or thrown out and the door was ripped off the hinges….a high quality steel door that had panic hardware and an unbelievable gasket, We had to add a countdown timer to shut down the motors on the blowers to the “emergency door” panic bar…..and there was a solenoid lock instead of a mechanical lock.

SO…what kind of foundation slab was there?

The second theory was that the piers or pilings supporting the foundation slab had failed and that the foundation cracked and then the build imploded. I still can’t get my head around the failure now that there was evidence of the pool just “sinking” or disappearing. If the sinking or slab failure started in the pool area, then once the slab failed, it might be logical for the building to shift….putting more weight on the front or poolside columns and then it toppled forward. BUT….I can’t reconcile the sinking pool….unless it went down so quickly and the first or the west portion failed and then the east portion.

Comments and discussion to help me understand is greatly appreciated.

BTW, my Brazilian roof failure was a three piece concrete arch or a trussed roof….put up with three cranes and held in place. If you make an arch or an arch with your thumb and first finger and have a short length of a dowel between the tips….that is the design. The dowel is the lower beam. NOW, to secure that three piece arch (from thumb tip to finder tip, you use a rubber band, the roof truss had the 3 piece arch and a linear beam….and there were 25 odd strands of 1/4” wire or cold rolled stock wrapped around the ends off the arch. The beam sat on a ledge on the side columns. During construction, there was a loom or a truncated cone on each end. This cone was pulled by a cable to tighten the strands or put tension on the “rubber band”. Once the tension was measured, buy the amount of torque or hydraulic pressure to separate the two end cones, the rebar was added to the cable loom and concrete was poured to encapsulate the strands and hold the cones in place. Water from a poorly designed and NOT Maintained roof seeped down on the end and the bare cables on the ends corroded and then finally, one or two failed….the three piece arch expanded and pushed the end columns out and the beam’s ledges let go or sheared. BINGO….the roof collapsed… there was 7 or maybe 9 sections of the roof and a total of 5 failed….

We chose STEEL trusses and rebuilt and also inspected and added reinforcements to the ones still standing….

Comments

  • GsoPackBackerGsoPackBacker Posts: 1,391

    Roo, I have not seen the video, but am curious if the pool can be seen in the clip at all. My first thought given everything else is that this "fact" is a red herring. What she saw and what happened may be two very different things. Power cuts, lights fade to black, and pool disappears. Who knows at this point, but the way the building fell reminded me of some of Griffin's finest demolition work.

    When I saw the initial pics and the questions about a bomb, I knew that was just media speculation and nothing more.

    Spent a summer working on a concrete construction crew and another doing testing on concrete samples so I find this stuff interesting.

    Here is a nice video and analysis based upon what is known to the public. It was a post tensioned slab and he talks about it in detail using available pictures. Interesting stuff.

    https://youtu.be/WJoTw4orM58

  • 1984Met1984Met Posts: 987

    Roo, good write-up. However, a few engineering courses lowered my gpa at State. So, I'll leave the analysis up to all of y'all.

  • AdventurooAdventuroo Posts: 3,859
    edited June 29

    The ONLY thing that STILL bugs me….is what happened to the POOL. It supposedly “Disappeared” based on a phone call from a lady that was on the balcony and looking out and was on the phone to her husband and told him…. 

    Cassie's sister Ashley Dean spoke to Sky News about her sister's last phone call with her husband, saying: "Suddenly she says, 'honey the pool is caving in, the pool is sinking to the ground'.

    "He said 'what are you talking about?' And she says, 'the ground is shaking, everything's shaking' and then she screamed a blood-curdling scream and the line went dead.

    SO….maybe what she saw was the pool deck caving in and that was right before her section of the building went down… presumably section 3….

     

  • TexpackTexpack Posts: 3,492

    I have always glazed over when the dirt movers (CE’s) started talking about foundation design in project meetings. I have also realized how much I want those guys to be really good at what they do.

    The whole inspection thing is another ball of wax entirely. You’ve got the I-40 bridge in Memphis earlier this year where the inspector pencil whipped the report and we almost had a tragedy. This time the inspector did their job and the right things didn’t happen in response. I too will be interested to hear what the structural folks have to say.

    On a human level this is just beyond awful. You just hurt for people that lost both parents or all their grandkids at once. It’s horrific. Prayers for all of them.

  • AdventurooAdventuroo Posts: 3,859

    GSO….

    Excellent source. I watched the video. Primer on PT or Post Tensioned concrete slabs.

    It is well worth watching to pick up the subtitles of the damage and the lack of, seemingly, concern. As my son is a home owner in a 10 story building in Bethesda, the HOA which is responsible for the building and the tenants pay the dues for management and reserves, the cost of repairs and the timeframes escalates and is, I presume, typical.

    OK…..BACK ON POINT. IF you watch the first video, follow the logic of the collapsed sections…..and DISREGARD the PT sections about the roof and the mid point….

    Josh Porter, Principal Engineer of Building Integrity added this footnote to the original YouTube video….

    After reviewing the original architectural plans, we now know this building was not constructed using post-tensioned cables. That was a working hypothesis during the recording of this video. The building is constructed using steel rebar reinforcement, however, the discussion of the post-tensioning system is still relevant for many other buildings.

    OK…wrong rabbit hole…..but his analysis of the type and sequence of failure could be a primer for CDI (Controlled Demolition Incorporated), I tore down two buildings and always wanted a third try with CDI and wanted to “push the button”.

    Josh is supposedly on vacation with family in Florida. He seems obsessed, but obviously is promoting his YouTube Channel that premiered in December 2020 and is an expert witness (for and against) in forensic building failure analysis.

    I watched a second one…..it deals with the planters and the leaks. The three columns that appear to have failed are in an area that is irrigated daily with deep planter. In that video he lays out the theory that three columns failed…..at the end (looking at the video) or closest side and once they went….it was a domino….

    https://www.youtube.com/watch?v=dSQq2FimiXY&t=168s

    Now…..this one deals with it also….the last one was very recent…..so this one also has more “info”. He also goes into some details about what is known and sort of debunks or does not emphasize the sinking theory

    NOW he has TWO....recorded last night.....Part 1 is interesting....and he makes a comment about asking a PE about X and expecting an exact answer....

    https://www.youtube.com/watch?v=WiQQv3RsWxk&t=102s

    I will be watching Part 2 since it will "premier" in 17 hours.... Will be interesting....

    https://www.youtube.com/watch?v=e3xrUkRtHQE

    Better diversion than Baseball and I HOPE NO ONE POSTS a score or who is winning as I am trying to expel that from my mind... I HOPE that Troll and the others will delete any info on the Games and the CWS...

    Also, my DW is, as I said, on a Holy Yardwork Terror and she has exempted my GS from the labor force as he has been exposed to Tonsilitous and we will be visiting relatives that will be traveling to Switzerland in a few weeks and they are under extreme isolation protocols for Covid and any OTHER malady known to mankind....

  • turkeydanceturkeydance Posts: 239

    "The failure was almost a perfect implosion demolition job."


    wow.

  • AdventurooAdventuroo Posts: 3,859

    D H Griffin does or did great work and they partnered with CDI from lime to time. David (Jr?) is now more of a developer. He was the final project manager for 911…..which is coming up on 20 years. And many HAVE forgotten

    if you read the various articles…..but step back and look at the debris field….the “failure” resulted in a failure or implosion that CDI would have been envious of in their earlier days. They are or,have been more precise….but for an unplanned event, this one sure measures up.

    whether it was a design failure or a fabrication failure or a job site failure…..the courts will debate.

    I remember the debate about the Crabtree Mall deck collapse. They did trace that failure to a fabrication issue. The column fabricator in SC left out about half the rebar in the ledge that was “built in” to the column, It got really COLD and the slab or deck contracted. That moved the mass out further on the ledge. Bingo,,the ledge sheared off. Once you lost the ledge on one section, all bets are off.

    This whole escapade sounds like the three or 4 columns failed…..that then was like a CDI “cut” sand then the building fell. CDI would have had more charges so that the sections came down straighter or more precisely. I assume that last nights demo was more precise and allowed the sections to fall straight….and protect the original debris pile.

    I have not done too much more. One expert spent 20 minutes on the 15 second of phone video….so I tuned out…

    I personally wonder if the article is correct and the steel was “light” and someone got a $100 handshake after they signed….

  • AdventurooAdventuroo Posts: 3,859

    Surprise….SURPRISE…S>U>R>P>R>I>S>E!!!

    Surfside building collapse: Multiple lawsuits seek to get answers, assign blame

    https://www.foxnews.com/us/surfside-building-collapse-multiple-lawsuits-filed

  • turkeydanceturkeydance Posts: 239

    Adventuroo, in your opinion, will this collapse lead to:

    1. multiple and expensive inspections for other towers?
    2. generate a moratorium on new tower construction?
    3. lawsuits coalesced into one gigantic class action?

    of course, none of us know, but i just want your opinion.

    thanks.

  • AdventurooAdventuroo Posts: 3,859
    1. yes. Another 10 story complex was forcibly evacuated yesterday. Residents were given 15 minutes to collect what they could. This MAYBhave been the condo that was cited earlier as having massive electrical and structural issues. there appears to have been a lot of inspections as part of the 40 year recertification process. However, it also appears that the reports were not exactly “front page news” and the HOA or Condo associations were not quick to notify or proceed.
    2. Probably not….but the plans and specifications will be scrutinized. I also suspect that the individual inspection entities will be more rigorous. The Miami Dade building code is considered as the gold standard. I have a friend that was a roofing consultant for 30modd years. He retired and became a project manager for a local private university in the “Villages” area. He had to bone up on the code to make sure that the renovation of the buildings and the new ones met code. The residential and commercial roofing specs from the Miami Dade code is what is being, generally, used on our coast. Typical cost is 25% more than the SE building code for a roof. Engineers will probably beef up their designs, just to make sure….IMHO.
    3. Good Question. Have no idea on how the units or buildings are owned. My son owns a unit or a condo in Bethesda. The building was an apartment building. The owner or developer sold the units to residents or “investors”. The HOA assesses the owners for all maintenance. The water, sewer and electricity is a Condo expense. There are no individual meters for such. The residents pay for cable, phone and internet. All the building repairs are funded from the HOA dues. His building is older. They have replaced the roof, renovated the pool, totally replumbed the HVAC system, etc. They have a single pipe HVAC water line. In the winter, there is heated water and each unit has a heat exchanger inside the blower or fan box. There is a single thermostat in each unit and forced air heat is the result. They shut down the system in the spring and the fall. They then do chemical cleaning of the pipes or system and change over to chilled water in the spring. I had a system in a plant and it is a nightmare. It took them almost 6 months to remove and replace the old piping as it was rusted and scaled up. The scaling reduced the heat transfer efficiency……..so….BOTTOM LINE. There will be a class action suit from the Champlain receiver (the HOA has been functionally dissolved) and that receiver will sue the engineering firm that did the “recertification inspection” in 2018 for malfeasance. In that they failed to properly convey the critical nature of the building and should have taken action to notify the city as well as the HOA.
    4. MY THOUGHTS….. I do not know the landscape, but suspect that many of these units are all that the “owners” have as far as assets. They may be living on fixed income. Some are elderly and their heirs are waiting for the estate to settle and will sell quickly. That is how my son’s building, in Bethesda…inside the Beltway, is populated. Maybe 1/3 professionals that have resources or are married with 2 incomes; 1/3 elderly that were original renters and bought when the owner/developer sold off individual units and 1/3 proxy owners that rent or sublet.
    5. The FL market has a lot of condos that are owned by snowbirds and they travel south for the winter. My son’s Ex In-laws have a studio apartment there and make the trip every year. Based on the news articles, the Champlain unit sounded like at least 50% were full time residents, of the Jewish faith. I suspect many of the units were empty based on the comments and the time that it took to go through the visitor’s log. So, these visitors were from all over and were thrilled to get an Oceanside condo.
    6. I foresee more “class action” activities aimed at the HOAs of all of the older buildings. There may be some reluctance on the Engineering Community to take advantage of lucrative “survey and status” work and I suspect that the 40 year recertification will be reduced to maybe 20….
    7. The city will be named in suits and such. Personally, there was probably not enough overt or “fatal flaws” in the columns and such to trigger a “shut it down and evacuate” report.
    8. The forensic engineers like the one that I posted will be there in droves and will be the ones in demand to testify for or against the original engineering firm and the city will be named, but removed quickly. If the guesstimate of $650K per unit is correct, then the value of the building was a bit over $100 Million. I do not know if the Homeowner’s policies will cover the “cost” of the structure. The HOA had maybe $40 Million. There will be a move afoot to kick that up to the market value of the units….
    9. It gonna be a mess…..and the lawyers and engineers and “learned professionals” that testify are gonna be in big time demand. If I were a senior partner in an Engineering firm, I would limit my work and not get into inspection…..but you could charge as much as you want…..but your professional liability insurance better be in the BILLIONS….
  • scouterprofscouterprof Posts: 407

    Relevant to what may happen in future here are a couple of articles making some of the points Roo makes https://therealdeal.com/miami/2021/07/08/surfside-collapse-a-come-to-jesus-moment-for-south-floridas-condo-market/

    Say one effect among others could be tearing down older buildings and putting up newer ones which will price current tenants out of market

  • AdventurooAdventuroo Posts: 3,859

    Meanwhile….

    It ain’t only the Condo HOA’s that got problems

    https://apnews.com/article/business-lifestyle-health-courts-miami-f2934f1febdb5e82eabe3be2bac0b026

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