Fascinating weld failures.

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I was watching a documentary on an oil rig tragedy recently (piper Alpha) and it led me down a bit of a rabbit hole of different tragedies. One stood out to me. Which was the 1980 sinking of the Alexander L Kielland Oil rig which killed 123 people. Doing some reading the rig sank because one of its legs failed from stress cracking. But when they did the investigation they found it was due to a 6mm fillet weld from the factory that held on a non structural bracket. https://en.m.wikipedia.org/wiki/Alex...and_(platform)Anyone have any interesting stories related to this kind of thing. I hate to hear about these kind of tragedies but the how and why of them away so fascinates me.Gear: Esab power compact 205 with tbi industries torch         BOC Smootharc 185dc tig         Miller Syncrowave 350LX
Reply:While not specifically welding related, the Kansas City Hyatt Regency walkway collapse is a fascinating study in the folly of making seemingly innocuous design changes without an understanding of the underlying physical forces and engineering principles.

https://en.wikipedia.org/wiki/Hyatt_...lkway_collapse
Reply:If look the joint they need a web reinforcement and a heavy washer.Also more harmonic engineering too. The code did not cover the load on walkway.  In California for walkway it is 250 pounds to square foot.Dave FYI Harmonic engineering is everyone dancing on the walkway.

Originally Posted by Wolfman

While not specifically welding related, the Kansas City Hyatt Regency walkway collapse is a fascinating study in the folly of making seemingly innocuous design changes without an understanding of the underlying physical forces and engineering principles.

https://en.wikipedia.org/wiki/Hyatt_...lkway_collapse
Reply:Every once in a while something happens. We saw a thing on a forum some insurance guy must have heard about cold weld when a hitch broke on a cargo trailer.  Anyone remember that, even from a pic coiuld see plain as day the tube was too light, of course that would put the blame on engineer instead of dumb welder.   I am actually amazed more doesnt happen considering the duty cycle and poor maint than does.  Think about the thousands of # iron faced on the hiway and being operated.   Commercial trucks get rudimentary inspection but lots of cars should be condemed seemes to go and manage to steer and stop every day.  I have old cars, I work on them, when I see one go by I know its not recent service with new tires.  When I am on auto forum its almost sacrilege to not replace every brake pad when it needs one with new after market racing parts.  I couldnt afford to keep brakes working if I toss a grand at every squeak, lots of stuff on cars dont get fixxed till breaking.   The oil platform proves we all miss one once in a while and usually its found before its tragic.  While a wheel coming off a boat trailer is common normally not tragic to the point it becomes a high statistic.  I think they do studies on car inspection and accident and the outright mechanical failure wasnt a huge factor.  Before someone blows up what a tragedy I used some disclaimer language,,, yes it happens but outright human error is sooooo much higher makes it less of a factor.www.urkafarms.com
Reply:I hgave been in a lot of hairy places but I never been on a water rig.  My neighbor was on one 11 years and said it was unnerving and never get used to it, hated every minute.www.urkafarms.com
Reply:My later job in the copper industry was heavily influenced by vibration and harmonics, I set up the parameters for every piece of equipment in the plant, I had to determine how much effect electrical phase interfered with equipment as well as gear pass, and bearing pass frequencies screwed with stuff and at what area in the "waterfall". The equipment can tell what RPM  frequency a piece of equipment will generate certain vibrations or harmonics. It's amazing to see it graph something going on at 2 times rotational speed or four times, this allows a vibration specialist to build a graph over time to see how these unknown vibrations effect machines.I remember one time when we were assigned to balance a 40 inch 3600 rpm blower, we had shut it down and hung a trial weight to get an amplitude & phase angle shift to calculate or needed weight. Upon restarting the blower the amplitude was so drastic that it ripped the threads out of the sole plate and went dog crap crazy, we shut it down and had to wait for it to stop on it's own, the only thing that kept it contained was the housing/volute. We had to fab a new sole plate & bed it in & re grout it. I realize this isn't directly a welding related failure, but does represent another area where things fail. In the last several years they got very involved in getting failure analysis done.Last edited by CAVEMANN; 04-13-2022 at 09:39 PM.NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINELET'S GO BRANDON!"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” BENJAMIN FRANKLIN
Reply:I recently (like a year ago...) read Two Tankers Down.  It details the sinking and rescue of two T-2 tankers that split in half off Cape Cod in the 50's.  There were multiple T-2 tankers that failed in similar conditions due to metal fatigue.  Though not weld failures, this topic reminded me of it.
Reply:Not a weld failure but plenty of harmonics!https://en.wikipedia.org/wiki/Tacoma..._Bridge_(1940)And from the link above a mother load of structural failures.   https://en.wikipedia.org/wiki/List_o..._and_collapsesLast edited by jrporter; 04-13-2022 at 10:24 PM.Tweco Fabricator 211iSieg X2 AMT radial arm drill pressAMT belt/disk sanderHF 4X6 bandsaw
Reply:I don't know if you're familiar with AvE on YouTube - but he has some pretty interesting takes on some recent structural failures of stuff that had NO good cause behind it. One of them (actually, I think more than one) was the failure of a ski lift (cable driven). Takes people from the bottom of a hill/mountain to the top. You might end up WAY up in the air during the transit. Anyway - one big reason they fail is metal fatigue. The other big one is poor maintenance.