Slab Requirements for 3rd Floor Shop

Veebee · Jun 24, 2018

Hi there, I'm currently investigating the slab makeup for a space I'm considering. It's the 3rd floor of an old factory (build in 1925), and the freight elevator is pretty darn huge and rated to 6000 lbs, so I'm not super worried... but I would like more info before moving a 4500lb lathe in. On the off chance, I can't get any information out of the owners is there anyone in a similar space that might be able to chime in?

Btw, hi I'm Victor and I'm new here, though I've lurked for a long, long time.

Ziggy2 · Jun 24, 2018

For starters, you need to know the floor load rating. It will be rated as Xlbs./ft^2.

A 6000lb freight elevator is not very much for a factory and kind of indicates that the floor might not have an adequate rating.

The problem with a lathe and other machine tools is the point loading on the floor. Most lathes will have the head end and might be like a 3ft.X3ft. base with like a 2X3 base on the tailstock end. That gives you 9^2ft. on the head end and 6^2ft. on the tailstock end.

If your lathe weighs 4000lbs., the headstock end will probably be at 3000lbs and the tailstock at 1000lbs. That means the headstock end will have a load of 333lhs./ft.^2 and the tailstock at 167lbs./ft.^2

A lot of the older buildings had floor ratings of 125-150lbs./ft.^2. There are was to work around this but you need to know exactly what you are dealing with and the state of the structure.

Usually, the best way to handle this question is hiring the services of a professional engineer that is licensed in the state the building is located in.

Above grade floors and over basements also tend to have vibration and resonance issues. Again solvable but not without engineering and money.

johansen · Jun 25, 2018

I would not find myself inside a 6000 pound rated elevator from 1925 with a 4500 pound lathe.

Anyhow bolt the lathe to a skid to distribute the load, also take a look at the frame of the elevator. if its a steel frame such as wrought iron C channel then you could easily determine if it will hold, but if the deck is wood only then of course you will need to distribute the load better. its not running on the original 1925 wire rope is it?

Slab requirements are usually for stiffness and long term stability, not vibration containment for metal working machines. If you really needed to, you could fabricate a welded frame a little larger than the footprint of your machines, fill it with cement re-enforced, and set it on top of 3 pads of rubber. or 3 car tires on their sides, filled with just enough air to lift the pad off the rim. you get 3 point suspension which means the building moving around won't twist your lathe, and vibration isolation for relatively little cost.

Veebee · Jun 25, 2018

Thanks for the advice guys. I think I keep holding out hope because the price is so right... but then it's right for a reason. When I get word back about structural drawings I'll decide the next move from there. The cost of bringing out an engineer might not make sense, if it's just going to be the first of many headaches to come...

BSCustoms · Jun 25, 2018

We operate a rather large machine shop on the second floor. 50ish machines. As heavy as 16k.

The old timers bitch about us needing to be on a better foundation, and while I fundamentally understand this, I think its more that they don't like stairs.

I agree on the load rating. If it checks out, go for it.

Ziggy2 · Jun 25, 2018

The building owner should be very willing to help with much of this. Be very cautious of an owner that does not take this seriously.

You and he are accepting a lot of legal responsibility if you over load the floor and the lathe ends up on the second, first, or even the basement. It also tells you if the owner takes this lightly that your own safety is possibly in jeopardy from others, if they overload the structure.

Not trying to make this into more then it needs to be but above ground floor operations require some homework.

triumph406 · Jun 25, 2018

As long as the floor has rebar in the concrete I wouldn't be concerned about the ability of the floor to support the lathe. the bigger concern would be the floor moving and the lathe needing occasional releveling

machtool · Jun 25, 2018

triumph406 said:
As long as the floor has rebar in the concrete I wouldn't be concerned about the ability of the floor to support the lathe.

Its a 93 year old building. What makes you think its concrete? The O.P Didn't say.

sable · Jun 25, 2018

I used to work in a factory built in 1903 ,the lifts were 4000lb but machines could be lifted with 10 ton cranes. The floors were about 2 feet thick concrete and the biggest machine would have been about 6 ton , you could feel the floor shake when a Cinci milling machine was put on rapid.

Strostkovy · Jun 25, 2018

machtool said:
Its a 93 year old building. What makes you think its concrete? The O.P Didn't say.

Given the thread topic is about slab requirements, it seems reasonable to assume it's a concrete slab instead of a wood or metal slab.

steve-l · Jun 25, 2018

There is no acceptable response for this query other than see an architect. Under no circumstances should the OP accept any advice from any public forum. This is a safety issue that can have huge liability and financial consequences. Further, even accepting the owner's word on floor loading is not enough. You must go to the city hall and look up the building records as well.

GregSY · Jun 25, 2018

A 93 year old concrete floor 3 stories up in the Building Code Nightmare/Earthquake Capital of the USA? Nothing to worry about lol. Just hire some gender-fluid undocumented migrant dreamers to run that lathe for a few weeks. 3 floors up, they're closer to heaven if it doesn't work out.

DMF_TomB · Jun 25, 2018

1) floor vibration will effects other machines. i have seen that effect precision grinding before.
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2) floor level changes daily as outside wall columns change temperature compared to internal building columns at a more consistent temperature
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3) floor level changes when you park a fork truck or a pallet that weighs over 1000lbs in spots near machine. if floor not isolated visualize everything on a trampoline and as big person moves around the 2nd person on trampoline obviously feels the weight shifting.
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just saying it depends on the machines and the expected tolerances. many machines leveled to .005" end up .050" out of level. for some machines it does not matter and for other machines it does matter

neilho · Jun 25, 2018

Why not just run some numbers/inspect yourself? Nothing magic about structural calculations- they don't require a PE to make them. Post a sketch here of the support structure, if you can. Lots of people here willing to help.

DMF_TomB · Jun 25, 2018

many a floor is more than strong enough to support load but doesnt mean it will be stable.
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you can put a machine on a trampoline or in a boat too. obviously you might get stability issues

Veebee · Jun 25, 2018

steve-l said:
There is no acceptable response for this query other than see an architect. Under no circumstances should the OP accept any advice from any public forum. This is a safety issue that can have huge liability and financial consequences. Further, even accepting the owner's word on floor loading is not enough. You must go to the city hall and look up the building records as well.

I agree completely. This is underway, already. My business partner is an architect, and he was the first one to bring this all up. I was just curious to hear about any similar success/failure stories to soothe my nerves as we sort it out.

Sent from my iPhone using Tapatalk Pro

DMF_TomB · Jun 25, 2018

Veebee said:
I agree completely. This is underway, already. My business partner is an architect, and he was the first one to bring this all up. I was just curious to hear about any similar success/failure stories to soothe my nerves as we sort it out.

Sent from my iPhone using Tapatalk Pro

.
i have often heard of vibration from one machine effecting other machines.

Rudd · Jun 25, 2018

I am an Architect, I am not your Architect.
If we are talking an elevated concrete slab, it is going to be really difficult to reverse engineer the loading. Besides determining how much steel reinforcing is in the floor, the actual configuration of the bars (are they modern deformed bars, smooth bars, square bars twisted into a spiral (yes, seen it) , etc.
the other question is *where* are the bars in the concrete. Reinforced mass concrete was still in it's infancy in this time. The placement of the steel in the concrete was not fully understood. X-ray of concrete only goes so far.
My mentor in school was the best preservation architect in Florida. There was a move afoot to preserve the old Florida Supreme Court building. Since he'd just restored the State Capitol, they turned to Herschel.
3 story tall, reinforced concrete. Original drawings on hand, the rebar placement looked suspicious.
They removed a portion of roof, and started loading the top floor with sandbags - load to be code loading + factor of safety, think boiler testing.
The whole building pancaked. Third floor hit the second hit the first.
Bright spot? Nobody was inside.

alskdjfhg · Jun 25, 2018

If your really worried you need to talk to someone with verifiable credentials and insurance. Not a bunch of people on the internet that have never seen or been in the structure in question.

DDoug · Jun 25, 2018

Rudd said:
My mentor in school was the best preservation architect in Florida. There was a move afoot to preserve the old Florida Supreme Court building. Since he'd just restored the State Capitol, they turned to Herschel.
3 story tall, reinforced concrete. Original drawings on hand, the rebar placement looked suspicious.
They removed a portion of roof, and started loading the top floor with sandbags - load to be code loading + factor of safety, think boiler testing.
The whole building pancaked. Third floor hit the second hit the first.
Bright spot? Nobody was inside.

Please tell me that Mr. Herschel turned to the camera's at that point and said
"TaDa".....

Slab Requirements for 3rd Floor Shop

Plastic

Stainless

Stainless

Plastic

Cast Iron

Stainless

Diamond

Diamond

Titanium

Titanium

Titanium

Diamond

Diamond

Titanium

Diamond

Plastic

Diamond

Stainless

Diamond

Diamond

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