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Glass Structural Sreength

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surjaan

Structural
Nov 20, 2009
27
I am checking the design of a 3/4" glass panel. If any one has bending, shear values and E for glass please let me know. One reference is ASTM E-1300. I do not have it.
Thanks
 
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IBC 2009 has some values under "Glass" I think these are prescriptive and not exactly what you want.

Call a mfg or Google it!!
 
Another reference is CAN/CGSB-12.20. Asking for the bending and shear values for 3/4" glass is like asking what the price of a red car is. There are different glass types, treatment types, load duration coefficients, etc.... all with differing values that need to be taken into account when checking glass for strength and deflection.
 
Elusive parameters! Contact the manufacturer or supplier.
 
ASTM E-1300. Tempered is something like 10.6 ksi.
 
There is no definite design stress for glass because it does not have predictable breakage characteristics. One can only reduce the probability of breakage by lowering the maximum strength level. For annealed glass under a 60 second load duration LOF recommends a Design Modulus of Rupture in flexure of 2800 psi to have a probability of breakage of 8 per 1000. I allow 1000 psi typically for annealed and 4000 psi for tempered for long term loading and have had no problems. E is about 10,400 ksi according to LOF.
 
Scoop-
ATEM E-1300 gives allowables for annealed, heat strengthened, and tempered for the 8/1000 probability of breakage. I believe annealed is higher than 1000.

Also, I might be mistaken, but I don't believe the duration of loading affects the strength unless you have laminated glass (because of loss of composite behavior with longer duration loading).

Do you have a better resource than ASTM E-1300 for glass design?
 
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