i've been thinking about the Surfside condo collapse. 🧵
i'm a bit hesitant to write about it, mostly because i keep thinking about the folks trapped in the rubble. it makes an engineering discussion seem a bit cold-hearted.
but engineering affects all of our lives -- which, on a daily basis, literally depend on engineers doing a good job. most people take this for granted. it's probably why a catastrophic failure like this can affect us so deeply.
these are just random thoughts. we won't know the root cause until NIST completes their investigation, assuming they're able to collect enough evidence to find one.
many news outlets are quoting a 2018 field survey report from a structural engineering company which mentioned water ingress causing major structural damage.
the articles typically tell this as a story where the heroic engineer points out a fatal flaw and gets ignored until disaster strikes. but that's not really correct.
the "major structural damage" referred to the pool structure and not the rest of the building.
the report discusses spalling and cracking in the support columns in the garage, which presumably helped support the rest of the building. but the text basically says "yeah this needs to be repaired or it'll just get worse" and mentions nothing about structural integrity.
i mean, if the engineers at this firm really did see a major structural problem with the building, you think they'd point it out at the beginning of the report, rather than starting out with a discussion about leaking sliding doors.
sure, you could argue that a structural failure of the pool could cause a cascading failure affecting the rest of the structure, but that's not mentioned in the report.
perhaps they should have gone to greater lengths to inspect all the reinforced concrete. the report mentions they couldn't inspect a lot of it because it was covered up by decorative concrete, pavers, and other building decorations.
so i don't view this report as any sort of "smoking gun." the engineering firm clearly didn't see the collapse coming, otherwise they would have made a lot more noise.
the engineering firm also put together a plan for repairing and restoring the building. it's 84 pages of architectural plans which you can read here: townofsurfsidefl.gov/docs/default-s…
seems like professional engineers ought to take a brief pause before applying their seal and signature to any document, and think "did i miss anything?"
that's all i have for now.
(disclaimers: i am not a licensed professional engineer, nor am i a civil engineer. take everything i say with a grain of salt.)
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a while ago i picked up this old DAT drive for a very good price. let's see if i can get it working!
it is the Mitsumi DK4-SS4001, a SCSI DAT drive.
took out a bunch of screws and now we're in! DAT drives use a helical scanning system just like an old VCR, but in miniature. the round thing in the middle is the rotating head.
let's try and get this paper tape reader working. I have no control board for it so this is going to be interesting
here's a 4-phase stepper motor driver from another project. I actually got this working a while back, so I can move the tape precisely in either direction.
this is the illuminator. it shines light through the holes in the paper tape up into phototransistors