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Re: wind: use Kd=0.85 if other loads in combination are zero?

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Kind of an aside:
I find the ASCE 7-05 has improved alot from the ASCE7-02 too.


On 12/11/06, Syed A Masroor <masroor(--nospam--at)eaworld.com> wrote:
My vote is for using Kd=1.0 for cladding.
  It is self evident that we should use Kd=1.0 for structures that have equal resistance capacity in all directions. Since some cladding is going to be subjected to the largest force, we may design all clading for Kd=1.0. Otherwise, when the wind does strike, we lose on some cladding. 
 
However, if only a small part of the building is clad, the probablity could come in to play.
 
Commentary to ASCE 7-02 section C6.5.4.4 offers some insight in to this.
 
Syed Masroor.
 
----- Original Message -----
From: Will Haynes
Sent: Sunday, December 10, 2006 3:56 AM
Subject: Re: wind: use Kd=0.85 if other loads in combination are zero?

If I were designing it, I would use the 0.85 factor for the cladding.
 
 
Will Haynes

 
On 12/8/06, MICHAEL LeCOMTE <michael_lecomte(--nospam--at)hotmail.com> wrote:
In ASCE 7, the wind directionality factor Kd is used in all wind calculations when used with the load combinations of section 2.3 and 2.4.  In Table 6-4 various values for Kd and for Buildings "Components and Cladding" is listed, with Kd = 0.85 if used with the Load Combinations.
 
If you are designing vertical cladding, it really only has wind load (I guess you could argue it has selfweight dead load, but this may not be in the same direction as wind load).
 
So, if the other load conditions happen to be zero, is it still appropriate to say you used 'load combinations' and therefore use the reduced load factor of Kd=0.85 instead of using Kd= 1.0?


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