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Zeus

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Posts posted by Zeus

  1. 2 minutes ago, The Ace of Aces said:

    Berkeley in 2015 - 6 dead 

    https://en.m.wikipedia.org/wiki/Berkeley_balcony_collapse
     

    Chicago in 2003 - 13 dead 

    https://en.m.wikipedia.org/wiki/2003_Chicago_balcony_collapse

    I am surprised it doesn’t happen more often  

     

    Well hopefully if everyone is following the ASCE7 and building code at the end there’s a compounding safety factor that is happening. The deflection limits usually control and so you could be nowhere near failure on beams and joists. There’s a safety factor on top of those pretty conservative load minimum estimates built into the AISC and NDS and ACI for steel, wood, and concrete as well. 
     

    The thing that gets me in construction is the things I catch during inspections, there’s not a bunch of inspections happening on some projects. 
     

    Working a big school job right now and I will say certain school districts even have different levels of required inspections that are taking place. Typically I work hospitals and higher education and it’s standard practice there but some school districts just suck and do the bare minimum or less. Thank God I’m not on any of those anymore and my kiddos won’t be going to school there. 

     

    28 minutes ago, jimmyjazz said:

    Yes, wiki is the ultimate arbiter of engineering design.  It was absolutely a dynamic failure related to resonance.  I won't argue this any more, believe what you want to believe.

    Actually the engineering is the ultimate arbiter. You said the GC blew it, which they did, but also the engineer definitely caused those deaths. Maybe you have the inside scoop from your dad about resonance but NIST didn’t say that was the cause. Is your Dad Ron Hamburger from SGH? 

    pg. 229-232

    image.thumb.png.95ccca1ad4d5f8d382acbbdc388fc727.png

    image.thumb.png.044f2531f65835ff0f95e395b9c2f843.png
     

    https://nvlpubs.nist.gov/nistpubs/Legacy/BSS/nbsbuildingscience143.pdf
     

    Just watch that video it explains it pretty clearly, simple statics —


    image.thumb.png.f705ab01898c299bab7574242ea2f43c.png

    Tough way to learn but every structural engineer studies the engineering failures that happened at this walkway because it was so catastrophic. Most deaths due to structural failure in US history and all. 

    • Hook 'Em 1
  2. 1 hour ago, GenXer said:

    I have a theory that the hardcore trump supporters are criminals themselves. They may engage in fraud, tax evasion, or other shady dealings. They rationalize their own behavior by comparing it to trump. Like, hey it’s cool if I don’t report all my income; the president doesn’t report all of his either.

    Wait, Trump supporters are Latin American immigrants working for cash under the table?

    • Fuck You 4
  3. 2 hours ago, elfenix said:

     "And the Democrats are worse!"

    They are all the same, Texas should secede. 

    https://apnews.com/article/russia-ukraine-2022-midterm-elections-business-elections-presidential-elections-5468774d18e8c46f81b55e9260b13e93

    Clinton was fined $8k for using campaign funds to pay for opposition research and classifying it as legal fees. Similar deal. 
     

    The real question is who is behind the curtain? The two WWE wrestlers out there - orange man vs dementia man. It’s got everyone arguing and fired up, but it’s all baloney. 
     

    Who in the MIC is running the show and are they planning to blow more money and get more Americans killed in another pointless war soon? Do they even have the bodies to throw out there? 
     

    Anyway back to regularly scheduled programming

    • Hook 'Em 1
  4. 1 hour ago, jimmyjazz said:

    Yup, that was the GC who did that.  My dad headed up the structural engineering group (Civil) at Missouri-Rolla at the time, and he got brought in to consult on the post mortem.  The contractor had changed some of the joint designs and ultimately the natural frequency of the structure ended up aligning almost perfectly with the dancing going on.  It all started to oscillate (think Verrazano Narrows Bridge failure) and eventually came down.  It was  horrible.

    Not trying to be a dick, but no, it was poorly designed and then changed to be an even worse engineering failure. 
     

    watch that video I posted above

     

    from wiki:

    The original design by Jack D. Gillum and Associates specified three pairs of rods running from the second-floor walkway to the ceiling, passing through the beams of the fourth-floor walkway, with a nut at the middle of each tie rod tightened up to the bottom of the fourth-floor walkway, and a nut at the bottom of each tie rod tightened up to the bottom of the second-floor walkway. Even this original design supported only 60% of the minimum load required by Kansas City building codes.


    This design change would be fatal. In the original design, the beams of the fourth-floor walkway had to support only the weight of the fourth-floor walkway, with the weight of the second-floor walkway supported completely by the rods. In the revised design, however, the fourth-floor beams supported both the fourth- and second-floor walkways, but were strong enough only for 30% of that load.

    Jack D. Gillum would later reflect that the design flaw was so obvious that "any first-year engineering student could figure it out," if only it had been checked.

     

    The original design was very fucked up then the changes were proposed by the steel contractor and approved over the phone by the engineer. The dancing didn’t help but they weren’t hitting a natural frequency to cause the collapse the walkways were just totally fucked up and barely able to hold their own weight.


     

  5. On 6/8/2024 at 9:18 PM, Deej said:

    So the balcony didn't collapse, the glass railing had had enough. 

    Ah I didn’t see that the first go-round as I didn’t want to watch people die. 
     

    Well guard rails are only good for 50 plf on the top rail or 250# concentrated load. I’d guess 10 cholas shoved entirely onto the guard = 4000# between supports at 6’ is about  660 plf or 13x over loaded. 
     

    I’ve always wondered this as people have asked me to sign off on guards before Marti Gras here in Galveston. It’s a risky thing since the code required loads may not be enough to resist what may actually happen in a huge party. 
     

    Glass guards actually have some high standards too I don’t think the glass was the issue, just nothing is designed for that kind of chaos. Bar owners fault sadly. 

  6. Well

    Balcony load is 1.5x the adjacent area, it’s an assembly so it’s 100 psf so they would use 100 psf anyway since it’s not to exceed 100 psf. 
     

    A person typically takes up 3 sf and weighs 150#. So you would think 100 psf is pretty conservative. You have some reductions for larger areas that may have been taken on girders but those were joists failing. 

    In this case you have 2 - 400# cholas crammed into about 2sf so we are overloaded about 200%. Still, I would’ve expected enough redundancy and considering the deflection limits, enough strength to keep it from complete collapse like that. 
     

    Probably built wrong or an engineer wasn’t even involved in the construction. 
     

    Sad, this is shit that should only happen in 3rd world countries. 

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