Cable Mullion

[rubenv317]

What is the allowable deflection in cable? Suppose I have 8 meters long cable mullion..

 

[jayrod12]

You're going to need to give more info regarding the application. maybe a sketch as well.

 

[KootK]

For a glass facade, on the range of L/50 under 50 yr winds to prevent damage to the glass and sealants. For seciceability wind loads, it's more about not frightening the villagers.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[EngineeringEric]

L/50? some flexible glass there!

Is this a handrail/guardrail mullion? then the answer is less than 2" ever or as per OSHA (USA?) or building code

 

[KootK]

The trick is to realize that your facade will be likely be assembled from multiple lites connected to the cables near the edges of those lites. As such, cable deflection results in essentially no glass deflection but a whole lot of rotation in the sealant joints between lites.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[EngineeringEric]

So an N-sided-agon. seems logical for that application

 

[KootK]

Exactly. Of course, I'm just guessing at what I think OP might be up to.

Glass itself can tolerate a surprising amount of out of plane deflection too. L/50 would be a bit much though.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[pratamahrs]

Do you know in what standard I can find the L/50 deflection limit? I've also heard that there is L/75 deflection limit too

Pratama H.R.S., B.Sc, M.Sc
Facade Engineer

 

[KootK]

I know of no code specifying applicable deflection limits pratamahrs. If you find one, I'd love to hear about it.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[rubenv317]

The amount of pre-tensioning load to the single cable will depend on the permissible deflection of the cable. While there are no standards mentioning this allowable deflection, it is worthwhile to know if it is better to prove by testing or by theory. L/50 would be ideal but up to what span?

 

[hokie66]

I don't think there are, as yet anyway, standards or codes which apply to this sort of facade. You just need to be a hero.