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The load bearing capacity of glass - to bear its own weight

Posted: Thu Jun 22, 2017 6:00 am
by Glass Isle
Hello,

I wonder if anyone could give me some advice.

I am looking for information about the load bearing capacity of glass - to bear its own weight.

I am working on a number of flat fused glass pieces. Each piece will be suspended from the ceiling from a single drilled hole - near the top, think of a pendulum or a mobile.

The pieces will be no bigger than 300mm x 300mm x 8mm (most will be much smaller and 6mm thick)

As the pieces will be suspended from a single drilled hole in the glass, I want to ensure that the glass can bear its own weight.

Does anyone know of any guidance or calculation to determine the capacity of glass to bear its own weight.

If anyone could point me in the right direction for information/advice I would be very grateful.

Many thanks

Re: The load bearing capacity of glass - to bear its own weight

Posted: Thu Jun 22, 2017 12:56 pm
by jim simmons
All I can think of right now is that a lot will depend on the area of the support piece that is in contact with the lower side of the glass.
If it is very small, it will not hold as much as if it is larger.
I know that isn't much help./
You might do a search on the "shear pressure" of glass.
Or words to that affect.
The other Jim

Re: The load bearing capacity of glass - to bear its own weight

Posted: Thu Jun 22, 2017 3:05 pm
by Brad Walker
There's a great deal of data on the load bearing capacity of glass shelves (even some online calculators), but they all require two support points, not one. What you're talking about is drilling a hole in the glass and suspending it from the ceiling, which adds such complexities as the size of the hole, type of screw or whatever, and the material you're screwing into. The size glass you're dealing with isn't very heavy (around four pounds/two kilos or so), I would think it would be pretty easy to do a few tests to find out how much weight would cause your particular setup to fail.

Re: The load bearing capacity of glass - to bear its own weight

Posted: Fri Jun 23, 2017 11:51 am
by DonMcClennen
I suggest you drill the holes big enough to allow a metal eyelet be inserted. These can be secured with a proper adhesive. This allows movement of the hanging cables to happen without causing abrasive stress on the raw glass at the hole.. Thicker (1/4") glass will accept 2 eyelets (one from each side). I've used this method successfully many times over many years. In from edge of glass at least 3/4" .

Re: The load bearing capacity of glass - to bear its own weight

Posted: Sat Jun 24, 2017 6:12 pm
by Glass Isle
Many thanks to you all @ Don, Brad and Jim. I appreciate you taking the time to consider the issue and put forward some suggestions.

Jim, I will search for "shear pressure". Don and Brad, I will also test your suggestions. I came across the following information online which isn't too dissimilar to your suggestion Don, although this was in relation to toughened glass not annealed fused glass:

1. The minimum diameter of a hole must be 5mm for glass thickness up to and including 5mm and for thicker glasses, at least the thickness of the glass being drilled.
2. The distance between the glass edge and the hole should be at least twice the glass thickness.

Thanks again

Glass Isle

Re: The load bearing capacity of glass - to bear its own weight

Posted: Sun Jun 25, 2017 12:51 pm
by Kevin Midgley

Re: The load bearing capacity of glass - to bear its own weight

Posted: Sun Jun 25, 2017 6:15 pm
by Glass Isle
Thank you Kevin that's great. He uses a method of hanging I haven't seen before.

Glass Isle

Re: The load bearing capacity of glass - to bear its own weight

Posted: Mon Jun 26, 2017 12:06 am
by Kevin Midgley
Best of all you won't figure out how exactly it is done by looking at the photos. :lol:

Re: The load bearing capacity of glass - to bear its own weight

Posted: Tue Jun 27, 2017 7:13 am
by Glass Isle
Kevin, I think it is similar to fixtures and fittings supplied by this company in the UK http://www.shopkit.com/case-studies/cla ... ss-design/

But these works both use two points of support and do not bear their own weight.

Re: The load bearing capacity of glass - to bear its own weight

Posted: Wed Jun 28, 2017 10:04 pm
by Kevin Midgley
yes that link definitely has the concept except that the ones I've seen are no way as visible as part of the art. Essentially invisible. That is why they remain a mystery.

Re: The load bearing capacity of glass - to bear its own weight

Posted: Sat Jul 01, 2017 11:06 pm
by Bert Weiss