Overstrength factor and allowable stress design (ASCE 7-05 12.4.3.2)

[PSwan]

I want to use allowable stress design in combination with the overstrength factor.

When the new code came out (2006 IBC), some colleagues and I came to the conclusion that equations 5-8 of ASCE 12.4.3.2 were off limits because IBC 1605.4 only provides for strength design in combination with the overstrength factor (equations 16-22 and 16-23).

Last I heard, there was supposed to be some sort of addendum/modification to the IBC making a provision to use ASCE 12.4.3.2 eqs 5-8.

Anyone know the status of such provisions being adopted? I am in California.

Thanks!

 

[PSwan]

Correction:

Thats ASCE 12.4.3.2 equations 5, 6, and 8 rather than "5-8".
And that's the second equation 5 not the first.
(What were they thinking?)

 

[JAE]

Look at this link at ICC:

http://www.iccsafe.org/cs/codes/Documents/2009-10cycle/ProposedChanges/IBC-S.pdf

Specifically page 99/370 on the pdf. It looks like these were proposed to the IBC last fall.
These were proposed changes to the IBC 2009 and this section (S47-09/10) seems to address your issue.

Also look on page 35/102 of this link:

http://www.iccsafe.org/cs/codes/Documents/2009-10cycle/ProposedChanges/CCC-Action.pdf

This latter link is the code correlation committee and it appears that this WILL show up in the IBC 2012.

 

[sandman21]

I know of no city, or plan review company in California, that would not have you apply overstrength where it is required. Don't have my codes with me and not sure what you are trying to apply it to but if you would use overstrength for strength use it for ASD.

 

[PSwan]

Thanks JAE. Good info.
I'm glad to see these changes are coming down the line.
I just can't wrap my head around it every time I have to mix ASD with LRFD.

 

[sandman21]

1605.4 applies to both ASD and LRFD. No change for the CBC required, they should just clarify the basic and alternative issue.