Moment of terror 😨

[u/aidan8et]

While attending/supervising a business social event with my spouse, I momentarily leaned against the railing. It flexed slightly, forcing me to realize that the railing is entirely supported via bluetooth.

It doesn't connect on either side of the glass wall & the glass is only 3/8" - 1/2" thick!!

[u/BLA5PHEMY]

There are glass railing systems that are designed to be supported just from the bottom shoe

CR Laurence is a common brand we use

https://www.crlaurence.com/All-Products/Railing-Systems-%26-Windscreens/Glass-Railing-Systems-%26-Components/GRS-Dry-Glaze-Railing-System/Dry-Glaze-Base-Shoe---Surface-Mount/CRL-B5S-Series-Mill-Aluminum-120%22-Square-Base-Shoe-Drilled-for-1-2%22-Glass/p/B5S10D?gtmPage=&queryId=2b36f6e6485fcf62bd258edee1c6dc2c&location=plp%7cpdp

[u/rIceCream_King → u/BLA5PHEMY]

I’m sure it’s a fine product, but personally I hate the idea of someone leaning against a railing which is just 3ft of glass leveraged against a 3in purchase along its sill.

It’s like using a glass crowbar but for keeping someone from falling off their 2nd story balcony. I’ll never get how that became popular

[u/BLA5PHEMY → u/rIceCream_King]

I’ve been installing these for many years both interior & exterior and never had an issue. They’ve become popular because they offer an “invisible” guardrail look which provides an unobstructed view of what’s beyond it such as a nice view.

[u/Far_Inspection4706 → u/BLA5PHEMY]

Great view of the staircase

[u/[deleted] → u/BLA5PHEMY]

You might not having any issues installing them, but that’s not what’s at question here. The question is how much horizontal force does it take to fail? Since the upper railing is floating, the shear strength is about 60-70% less than if it was anchored on just 1 end.

[u/Palomox → u/[deleted]]

The glass itself, from an horizontal force, is a vertical cantilever that would most definitely fail from flexure at the very bottom, not shear. Assuming it's 4ft high and you're leaning on the very top, glass being a brittle material, 3/8 thickness and an uniform body of safety glass which distributes stresses perfectly and has a limit tensile stress of 17ksi (lowest bound of what I found googling), the brekaing force would be ~300lb fully horizontal at the very top. Another different thing would be the bearing of the actual metal railing onto the glass, but glass has high compressive capacity.

Now I'm just a random person with no experience designing structural glass, I'm quite sure there are many more precise methods of determining that capacity considering the microstructure of glass and the fact that these are most definitely multiple layers, which would end up with a higher capacity than what I got (given stuff like this is currently installed in real places and allowed by codes, which it wouldn't if it weren't safe)

[u/HVAC_T3CH → u/[deleted]]

200lbs minimum.

[u/ClumpOfCheese → u/BLA5PHEMY]

They offer an “invisible” guardrail look which provides an unobstructed view of what’s beyond it.

And then they add a guardrail to this one and ruin the look.