Seismic Restraints for Lathes?? - Page 2
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  1. #21
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    Quote Originally Posted by Illinoyance View Post
    If you use the anchor bolts specified by Nardini they will withstand any foreseeable seismic forces. Mine, on the other hand, just sets on the floor.
    I have thought of that but if the slab splits, the lathe will get ripped apart. I have experience mounting sensitive equipment on warships. The shock mounts absorb energy. The HVAC seismic guidelines recommend similar energy absorbing devices.

    My current thinking is to bolt L brackets to the floor the 4 corners of the lathe to contain lateral movement. The L brackets would have rubber pads between the brackets and the lathe. In addition, fit Z brackets to restrain the lathe from tipping.

    If I aim to keep the lathe in place with 2g force plus 100% safety factor, the brackets would need capacity to withstand 4000kg force (or more correctly ~40kN).

    Dazz

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    Quote Originally Posted by plastikdreams View Post
    They have built it up to being a cataclysmic disaster, but will it be? I really don't want to find out lol.
    Where I live, earthquakes are routine events. The Geonet website tracks them. I am most concerned about a relatively common 4-5 earthquake. A quake of that strength doesn't break the house (it creaks and moves around quite a bit) but it could tip the lathe over.

    Dazz

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    Quote Originally Posted by DocsMachine View Post
    ... the Good Friday Earthquake, which was something like a nine point two, and lasted something like five minutes.

    Damage was extensive, of course, not even counting that from the resulting tsunami. But, if you look at some of the pictures, you'll see largely intact buildings, whose major damage was largley due to the ground underneath them collapsing.

    In other words, it wasn't necessarily the shaking that did them in (although that did indeed cause considerable damage) it was the fact the ground beneath them essentially liquified and sloughed.
    Umm, you forgot to mention that there weren't any buildings in Anchorage at that time My two-story high school was halfway destroyed, they had to take the second floor off and rearrange it. The L street apartments were a twisted wreck for several years, before they pulled the building down. There was one other tallish concrete structure that was destroyed but I forget the name. Anchorage was the frontier then

    Anything higher than two stories and not made out of nailed-together pieces of wood ? Pretty well destroyed. Penney's fell down, L street ruined, much of downtown (all three blocks of it) was wrecked. Wally Hickel got a lot of acclaim for putting up a four-story building later, to "proves his faith in Alaska."

    btw, they have built on the two blocks of Turnagain across the street from us that disappeared into Knik Inlet. I guess the danger of earthquakes has passed now

    And in that kind of case, it doesn't matter how well you've anchored your lathe, or how deep your slab is. It's gonna go no matter what.
    That's really the bottom line. In a real erthquake, just get outside away from falling stuff or kiss your ass goodbye. In a city, from the Big One, there's nothing you can do. The roof falling on top of the lathe will be a bigger problem

    Quote Originally Posted by dazz View Post
    I am most concerned about a relatively common 4-5 earthquake. A quake of that strength doesn't break the house (it creaks and moves around quite a bit) but it could tip the lathe over.
    Doubt it. The Battle of the Bay quake just made my machines rattle and slopped sulfur oil all over the floor. Made some cracks and stuff but nothing was in any danger of falling over. And yeah, you could see waves in the street but lathes are tough. They don't tip over that easy.

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    Quote Originally Posted by EmanuelGoldstein View Post
    just get outside away from falling stuff or kiss your ass goodbye.
    The correct response is Drop, Cover, Hold. That's something that every school here has taught the kids for decades.
    Getting out of a building during an earthquake, especially multi-story buildings is really dangerous because of the amount of stuff (glass, concrete etc) that falls off the outside.

    Dazz

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    When a lathe is transported, many times it's bolted firmly to a wooden skid.

    Build one, and on the front, add a standing platform to bring you up
    to the original floor height.

    Lathe can slip during a quake, but not tip.

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    Quote Originally Posted by EmanuelGoldstein View Post


    Doubt it. The Battle of the Bay quake just made my machines rattle and slopped sulfur oil all over the floor. Made some cracks and stuff but nothing was in any danger of falling over. And yeah, you could see waves in the street but lathes are tough. They don't tip over that easy.
    Whether a lathe will tip over depends a lot on the specifics of the quake. A close and shallow quake will have sharp motion. The floor could simply slide under the lathe. If the quake is deep and at some distance, and the ground swings backward and forward, then a lathe could swing in harmony like an inverted pendulum until it tips.

    Earthquake damage is never evenly spread. In the last major quake here, my house and contents were fine. Specific apartments on some floors in some buildings looked like they had been trashed by rampaging football hooligans. Some new tall buildings survived but were unserviceable and later demolished (including one I worked in), while older, weaker small buildings remained serviceable.

    Dazz

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    Quote Originally Posted by dazz View Post
    The correct response is Drop, Cover, Hold.
    You drop cover hold. I'm going outside like the roadrunner. Worked in a 9.2 and I'm sticking to it.

  8. Likes adama, Greenwud liked this post
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    I'm with Manny on this. 1994 Northridge earthquake, our shop was 4 miles from epicenter, 2 Shoda dual pallet gantry routers not bolted down moved a few inches. Corner of the shop moved a couple inches too, roof collapsed, sprinklers went off yada yada yada. Everybody was in the yard at the first jolt.

    Steve

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    Hi
    If you are inside a building, you should try to get to a strong point. eg. a door frame.

    There are no certainties with earthquakes. Risk is a balance of probabilities.
    The area immediately around the exterior of a building is a high risk zone.


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    Quote Originally Posted by dazz View Post
    The area immediately around the exterior of a building is a high risk zone.
    Very true. I work on a campus with several four story office towers, all steel framed but with brick veneer all the way up. In a heavy quake, sheets of brick will be coming down, and four of the five entrances to each tower have no protective overhang.

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    In contrast, single floor wooden framed houses have proven to be resilient.

    This house was located right over the fault line. It was thrown 10m off it's foundation and wrecked but still standing. No one inside was hurt.

    The biggest risk is falling chimneys.

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    Quote Originally Posted by dazz View Post
    In contrast, single floor wooden framed houses have proven to be resilient.

    This house was located right over the fault line. It was thrown 10m off it's foundation and wrecked but still standing. No one inside was hurt.

    The biggest risk is falling chimneys.

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    100% agree- The value of a flexible, resilient structure cannot be underestimated in a good quake. Timber frame, iron roof, pile foundations and lots of BIG nails were the values of old. Christchurch 1 and especially 2, Wellington, Gisborne, Edgecumbe and Napier have demonstrated the value of resilient buildings.
    None of that bullshit drywall bracing. It's strong once and then it's broken and F'n useless- quakes have a way of happening in clusters. Ply brace and steel straps.

    WRT your lathe...
    Let's just say that the reinforcing is in the middle in theory only, because concrete placers are intrinsically lazy and some are absolutely dishonest. 200mm of reinforced concrete is a good start because lots of modern houses that were demolished in Christchurch 1 were built on 100mm of unreinforced concrete because only recently have people been awakened to the idea of quakes in the good city.
    I'm gonna say here, right now that if your 200mm slab of properly reinforced 20 Mpa concrete is popping and breaking, the lathe is the least of your worries.
    For minor movements, fit thick steel plates under the jacking screws with fibre or lead pads against the floor. Fasten down with drop in or chemset anchors at the anchoring points, and fit studs long enough for a substantial die spring under the nuts.

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    Quote Originally Posted by Greenwud View Post
    I'm gonna say here, right now that if your 200mm slab of properly reinforced 20 Mpa concrete is popping and breaking, the lathe is the least of your worries.
    So it would surely seem! Quick and dirty could be as simple as slightly slack chain to spaced pads so as to resist toppling. Add elegance, later.

    Advance warning, the seismologists usually discover they actually HAD some of only a month or so of reviewing data AFTER the damage is already done.

    IOW "You don't GET any!". Next one could come any time.

    "Do SOMETHING Lootenant! Even if its WRONG!"



    For minor movements, fit thick steel plates under the jacking screws with fibre or lead pads against the floor. Fasten down with drop in or chemset anchors at the anchoring points, and fit studs long enough for a substantial die spring under the nuts.
    Or a few Bellevilles. Or elastomer's off a vehicle cab/body or motor/transmisison mount. Good advice in general, Earthquake zones or otherwise, yah? Adding that ration of "elegance". Later.


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