Need Help!- Seismic anchoring of CNC's

[protogregg]

We just installed two Haas CNC's (VF-2, VF-3YT), and were told by the city that they need to be anchored to the floor for seismic purposes. The inspector told us that in a "seismic event" he feels these machines could "skip across the floor and crush someone against a wall". I think he is pushing for permit fees, but we can't really fight the city. Does anyone have any experience in anchoring these machines for this purpose? Do they need to be anchored for this reason? Please help if you can, as we can't even bed and use the machines until we figure this one out.

Thanks

[Geof]

I think they are stretching a point , I am in a seismically active area and have never heard of this. The inspector "feels" they could skip across the floor? You are correct about it being difficult to fight City Hall, it is also difficult to reason with idiots so you have a double whammy.

However, his 'skipping' across the floor is baloney and depending on how friendly the people who know about siesmic stuff are at your local university, if you have one, you could get data to validate or invalidate the skipping scenario. In a seismic event (I always thought they were called earthquakes) it is the ground that moves either horizontally or vertically, it can move fast and in the 1972 earthquake in Southern California (I think it was '72, it was the one that knocked down a Veteran's Hospital I think) accelerations of greater than 2 g's were recorded and similar values occurred during the Northridge quake. With these accelerations the ground slides sideways under things so it is the ground that is skipping around not the machine. But the ground does not move very far and this is where a university seismologist may be able to give some information. There will probably be records they can refer to to find the maximum lateral displacement that has taken place in prior quakes in your area. If the machine is further away from any walls than the maximum displacement ever observed no-one is going to get crushed between the machine and the wall. The wall might fall down and crush the person but that is a different matter.

However, having bored you with a bunch of stuff I will say what I would probably do because it is always a losing thing dealing with idiots. Did your machines arrive on shipping pallets? There are bent metal straps that are held on the levelling screws and bolted to the pallet. I would simply level the machine then install these metal straps in much the same manner they where on the pallet but they will be bolted to concrete anchors in the floor. You can tell the inspector that they machine is secured even more firmly than it was for shipping because now these straps are secured in concrete not wood.

[stevehuckss396]

Try getting in touch with one of the anchor manufacturer's like red head or something. Most times all seismic means is moving up in size or adding a few extra anchor's than a standard installation. Get a recommendation from a anchor manufacturer and the city will have a hard time disputing their expertise.

[jnsane84]

In my honest opinion I think if you had seismic activity to the magnitude that it would "skip" a 7000lb machine accross the floor, you would have far more to worry about than whether or not it will pin someone to a wall that is probably already fallen. Of course this a truely uneducated assumption since I have never experienced or lived in an area affected by seismic activity.

As for an answer to your question of anchoring, In the past we used Epoxy seated anchors for gantry's and extremely large equipment. If the inspector is that concerned with machines skipping accross the floor and crushing people I would invest the time and effort into using the Epoxy seated anchors. I included several links below that may help you out.



http://www.williamsform.com/Concrete...e_anchors.html

http://www.simpsonanchors.com/catalo...set/index.html

http://www.sierraanchors.com/Chemica...veAnchors.html

[mxtras]

Contact Unisorb - http://www.unisorb.com/

These guys have lots of logical solutions to machine isolation and anchoring that might make the butthead inspectors arguement go away.

Scott

[Geof]

Part of the problem of dealing with an Inspector who comes up with the 'skipping' machine idea is that there is a little element of possibility in it.

The probability is another matter; you would need the machine close enough to the wall, and a person between the wall and the machine, and the ground movement would have to be in the correct direction, and the rate at which the ground moved would need to be fast enough that the floor slid sideways under the machine, and the wall would have to be anchored much more firmly than the machine or it would just get left behind by the ground moving and the machine and wall would not get closer.

But, pigs might fly under the correct conditions, so maybe it could happen. But I still think it is an asinine worry, however, telling the Inspector he is a brainless twit may not be productive.

[cam1]

Hi:
Just my 2 cents worth. I routinely work with all the different types of inspectors(good cop, bad cop,blocker etc.), It's easier to move past this by "keeping him happy". This basically means showing him what you intend on doing to meet the guidline(s). It's OK to ask for the code he is citing under the pretense that you would like to make sure to "conform". The city has alot more resources to fight you. It may seem unreasonable, and I agree, however it won't cost much to comply, certainly cheaper than ticking him off, and being prevented from running the machines.

cheers

[apache405]

hmmm.... I hate inspectors who do that. I think that the idea of using the shipping anchor points is a good bet.

The one problem with drilling anchors into the floor is the depth of your floor. I was bolting a 500lb rack of audio gear to the floor of a high school press box and I thought the floor was 6" inches thick, (it was 4" thick), and I drilled clear through the floor. Also, if you are leasing or renting your shop space, your landlord may have something to say about you drilling the floor up, especially if you building is on a slab foundation.

Good luck with your quagmire of city inspections!