Heavy Engineering Hack Chat

Immense and in motion

Wednesday, September 14, 2022 12:00 pm PDT Local time zone:
Hack Chat
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Andy Oliver will host the Hack Chat on Wednesday, September 14 at noon Pacific.

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Here at Hackaday, we focus mainly on engineering at the small end of the spectrum. Millimeter waves, nearly microscopic SMD components, nanoscale machines like MEMS accelerometers, and silicon chips with features that measure in the nanometer range. We've all become pretty good at wrapping our heads around problems at the wee end of the spectrum.

And while all that tiny stuff is great, there's a whole, big world out there to explore, with big engineering to solve big problems. Think of things like dam spillways, lift bridges, and canal locks -- big stuff that still has to move, and has to do it safely and efficiently. Those are problems that demand an entirely different way of thinking, and skills that not a lot of us have.

Andy Oliver works in the world of big, movable structures, designing control systems for them. He'll drop by the Hack Chat to discuss the engineering that not only makes these structures work but also keeps them safe and reliable. If you've ever wondered how big things work, you won't want to miss this one.

  • Hack Chat Transcript, Part 2

    Dan Maloney09/14/2022 at 20:05 0 comments

    morgan12:52 PM
    huh, yep

    Andy Oliver12:52 PM
    Hah, yeah

    Andy Oliver12:53 PM
    That reminds me that we have to deal with cathodic protection sometimes, too

    Andy Oliver12:53 PM
    So, though we don't get to do the fun work of programming a PLC, we have to be generalists and be able to light the control room appropriately, energize the motors, and prevent corrosion of the foundation

    Dan Maloney12:54 PM
    And make it all still work while it moves

    Andy Oliver12:55 PM
    Jack of all trades master of none? That's why these projects include A LOT of people.

    Andy Oliver12:56 PM
    Thinking about the wind load question... we also have the emergency stop load, too. The mechanical engineers design the system so that the brakes can hold it against the wind. But the brakes also need to NOT break anything if you hit the emergency stop button at full speed.

    Andy Oliver12:57 PM
    It's a balance, and it's partly achieved by tweaking these hydraulic controls on the brakes to make them set over a few seconds, hopefully decelerating the bridge comfortably

    Andy Oliver12:59 PM
    In some cases we have to fix up an old bridge designed to different standards. In those cases we might need a certain motor for normal operation, but that motor has the ability to provide a lot more torque at starting. We've had to ensure that the motor controller does not allow the motor to produce more than a set amount of torque based on the mechanical calculations in these cases.

    Andy Oliver12:59 PM
    Typically on a new system they are designed so that the bridge can jam and the motor can generate full torque and not break anything.

    Dan Maloney1:01 PM
    So we've gone through our hour and we've got to wrap it up. Andy, a big thank you for your time today, this was really interesting, I really appreciate it! And thanks to everyone for stopping by!

    Andy Oliver1:01 PM
    Yep, sure. Thanks for having me.

    Dusan Petrovic1:02 PM
    Thanks everyone!

    Dan Maloney1:02 PM
    Thanks all!

  • Hack Chat Transcript, Part 1

    Dan Maloney09/14/2022 at 20:04 0 comments

    Dan Maloney12:00 PM
    Hello everyone, welcome to the Hack Chat! I'm Dan, I'll be moderating today along with Dusan as we welcome Andy Oliver. We're going to be talking about Heavy Engineering, which I'm really looking forward to. Hi Andy, are you online yet?

    201 joined  the room.12:01 PM

    Dan Maloney12:02 PM
    OK, maybe he's running late or logged in somewhere else. Hold on a sec while I see what I can do...

    Andy Oliver12:02 PM
    Oh my that was dicey. I made it!

    Dan Maloney12:03 PM
    Hey, welcome -- no worries!

    Andy Oliver12:03 PM
    Was trying (and failing) to log in on my phone to let everyone know... but here I am on a real computer.

    Dan Maloney12:04 PM
    And before we get started, I just want to note the fact that Andy is the first Hack Chat guest I've ever booked through filling out the host form! I've gotten plenty of responses there, but they've been -- err, crackpots I guess is the right way to put it.

    Andy Oliver12:05 PM
    Glad to help.

    brianmhff66112:05 PM
    I feel like the Cessna pilot with 100 hrs sitting in briefing room for sr71 sled jockeys

    Dan Maloney12:05 PM
    Andy was the first with a real idea and some cool stuff to talk about. So maybe you can start us off with a little about yourself?

    Andy Oliver12:06 PM
    Sure. I'm an electrical engineer at a firm that, among other things, designs and inspects movable bridges.

    Andy Oliver12:06 PM
    "Drawbridges," though some movable bridge engineers get picky about that term (not me)

    Andy Oliver12:06 PM
    I studied electronics but ended up in this job. Like always, college is nothing like real life, but useful none the less

    Dan Maloney12:07 PM
    I can see why, really -- there was a railway bridge in the middle of the Connecticut River that pivoted on a central axle. But people still called it a drawbridge

    Andy Oliver12:07 PM
    Instead of electronics, we do controls (but not fancy stuff like you learn in university), electric power distribution (on the site), big motors, lighting, and some other randomness

    Andy Oliver12:08 PM
    Yep. That's technically a swing bridge

    Andy Oliver12:09 PM
    We have vertical lifts (tower drive and span drive), bascules (from the French for seesaw), pontoon bridges (several in Washington state because of the DEEEEEP fjords there... you can't get a foundation big enough to reach the bottom)...

    Dan Maloney12:10 PM
    So it seems like there wouldn't be a huge market for movable bridges, at least for building new ones. But I'd imagine there's a lot of work in repairs and upgrades, right?

    Andy Oliver12:10 PM
    That covers the main types. Occasionally we get tangled up in movable roof work and locks on waterways

    Andy Oliver12:10 PM
    That's about right. They get replaced after about 100 years or so in most cases.

    Andy Oliver12:10 PM
    And it costs a lot to build a new bridge... hundreds of millions for a fancy pants one

    Andy Oliver12:11 PM
    So they keep them going with repairs

    Andy Oliver12:11 PM
    That said, just between Florida and Louisiana there are about 200 movable bridges among all the owners (state, local agencies, railroads especially).

    Andy Oliver12:12 PM
    FL and LA are about tied for the most movables and probably have more than half of the country's inventory if I'd have to guess

    Dan Maloney12:12 PM
    Really? I'd have been an order of magnitude low if you'd asked me to guess.

    Andy Oliver12:13 PM
    Yeah, where I live in South Florida, the Florida DOT district that covers a handful of counties near me has 37 or so movable bridges.

    Andy Oliver12:14 PM
    That's more than most other agencies, but we still... Back in the 50s after WW2 the barrier islands here underwent a great deal of growth quickly.

    Lars joined  the room.12:14 PM

    Andy Oliver12:14 PM
    So they had to build a bunch of bridges fast to keep up with population growth as people came back from war, had kids, used the GI bill to get educations and jobs, etc.

    Andy Oliver12:15 PM
    I wondered if there are any participants here that have such a bridge on their commute and curse it every morning.

    Lars left...

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