This is a fascinating thread. I know nothing about design of glass structural elements, however since recently seeing the "glass box" and the glass bridge, etc., in the Apple stores in Manhattan I am in awe of those who design such structures.
Regarding your comment about the code not requiring point loads: That may be so, however some of the glass railings I've seen are supported by pairs of "buttons" at the side of the concrete floor or stair (e.g., NYC MOMA and Phoenix Art Museum, IIRC), which seems to be pretty much the same structural condition.
Ralph Hueston Kratz, S.E.
Richmond CA USA
In a message dated 3/12/09 10:33:34 AM, seaint2@truesdellengineering.com writes:
I look at the glass from a minimum tensile stress, and for simplicity
assume that any stresses are tensile. When I get $20k to do a stair
rail, I'll be less conservative. Again with the flaws - there is no way
to economically specify maximum flaw size, so I use values for allowable
stress from the glass industry. Finally, point loads aren't part of the
guardrail standard for the building code, only pressures (50lbs over 1
ft^2), unless it is used at the rail itself, in which case you can apply
a point load in FEM and see the stress contours.
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