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Re: Glass railing Redux

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I tried to send two photos I recently took in the new wing of the Phoenix Art Museum, but they bounced -- "too big."  They show 1) a glass railing with NO top rail or continuity, each piece of glass attached to the edge of a concrete slab with 4 big "buttons," and 2) a glass stair railing with a handrail hanging on the side of it, each piece of glass attached to the edge of the concrete stair slab with *2* of those shiny "buttons."  It really looks neat; I wonder how they do it.  It's thick glass, thicker than 1/2" I believe. 


In a message dated 6/7/07 5:32:33 PM, Mlcse(--nospam--at) writes:
How wide is the glass between the bolts.  If you check the glass in out-of-plane bending along a yield line through the bolts, you will probably find it doesn't work in flexure.  Yes you need the top rail continuous over three pieces of glass incase one piece breaks, but each individual sheet of cantilevered glass has to be checked for the guardrail loading acting at the top of the glass, and generally you need a piece of glass 4 feet wide to resist the applied loading from my experience for 1/2" thick glass.
Michael Cochran
In a message dated 6/7/2007 8:19:52 A.M. Pacific Daylight Time, tarooky(--nospam--at) writes:

The glass railing will have a top rail, but my understanding is that the top rail is required
over at least three panels so that if one fails, the top rail can still be supported. however,
the glass panel is still cantilevered - kind of - from the corners, with four bolts in each corner

Tarek Mokhtar, SE
Laguna Beach, CA

I don't think this is going to work with just a bolt in the lower corners of the glass, your stresses are going to be way to high.  You need a continuous shoe for the glass to frame into if its a cantilever glass guardrail, and the glass needs to be about 4 feet long in the shoe to work to handle the 200 pount point load at the top of the glass railing (especially if its only 1/2" thick glass).  There are design requirements in the UBC and IBC for glass railings that a lot of people either don't know about or choose to ignore.  I have seen the glass work with a bolt in each corner it you have a continuous rail above the glass to act as the guard rail, and the glass is just an infill panel between the top and bottom continuous rails between vertical steel stanchions.

Michael Cochran SE

-----Original Message-----
From: Tarek Mokhtar
To: seaint(--nospam--at)
Sent: Wed, 6 Jun 2007 6:48 pm
Subject: Glass railing

Does anybody know of a way to calc glass panels acting as deck guardrails that are supported 
only at the lower two corners by bolts? I have seen them around, just not sure how to make them 
work, or if somebody is interested in taking the job, please email me privately 
Thanx in advance 
Tarek Mokhtar, SE 
Laguna Beach, CA 

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