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ACI 318 Appendix D

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The reason AISC 341-05 negates the seismic requirements of Appendix D is because the Appenix D requirements are based on the load combinations of ASCE 7-05 (same as ACI 318-05 load combos) which is different than the AISC 341-05 requirements which are based on member capacity demands.  Essentially what AISC is saying is that they want the members of the lateral force resisting system to yield before the anchorage to the foundation does. This load is typically much higher than the load combination demands because the member capacity, for instance, is based on RyFyAg. Ry is a factor in AISC 341-05 that increase the yield strength of the memeber based on what the upper bound of the yield strength of the material is, like ASTM A36, etc.
 
In a nutshell essentially AISC is saying the anchorage must be designed for higher forces than what the load combinations that Appendix D is based on.
 
I hope that explains it.
 
I failed to mention the great exception to the AISC requirement and that is the all inclusive load generated by "what the system can deliver" exception.
 
Andre Sidler, S.E., P.E.
Quantum Consulting Engineers
Seattle, WA
 
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From: "Joseph R. Grill" <jrgrill(--nospam--at)cableone.net>
To: <seaint(--nospam--at)seaint.org>
Subject: RE: ACI 318 Appendix D

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I was thinking the same thing. I don't see how AISC can negate ( as William
says ) an ACI code requirement for anchorage in concrete. If there was ever
a problem I don't think I would call ACI as a witness for my defense if I
used the AISC code to do (or not do) the anchorage design, but I bet the
other side would call them in a minute.

Joe Grill



From: William.Sherman(--nospam--at)CH2M.com [mailto:William.Sherman(--nospam--at)CH2M.com]
Sent: Sunday, April 19, 2009 8:45 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 318 Appendix D



Section 8.5 of AISC 341-05 essentially negates the seismic provisions in ACI
318 Appendix D for anchor bolts at steel column base plates. It is
interesting that the "steel code" allows exceptions to the seismic
provisions of the "concrete code"!?



Bill Sherman

CH2M HILL / DEN

720-286-2792






_____


From: Jules [mailto:JulesG(--nospam--at)socal.rr.com]
Sent: Sunday, April 19, 2009 9:38 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: ACI 318 Appendix D

AISC 341-05 is better known as "Seismic Provisions for Structural Steel
Buildings"

----- Original Message -----

From: Larry Hauer <mailto:lhauer(--nospam--at)live.com>

To: Struct. Eng. Assoc. <mailto:seaint(--nospam--at)seaint.org>

Sent: Sunday, April 19, 2009 8:16 AM

Subject: RE: ACI 318 Appendix D



Jules,

What is ACI 341-05? It appears to be a manual I don't have. Can you tell us
what Section 8.5 says?

Thanks in Advance

Larry Hauer S.E.



_____


From: JulesG(--nospam--at)socal.rr.com
To: seaint(--nospam--at)seaint.org
Subject: Re: ACI 318 Appendix D
Date: Sat, 18 Apr 2009 08:39:21 -0700

Bill,



I've been reading through all the answers on this subject but nobody
mentioned the exception on AISC 341-05 8.5. It solves most of the problems
for anchoring column base plates, I use it.

Regards.



Jules

----- Original Message -----

From: Bill Allen

To: Seaint

Sent: Thursday, April 16, 2009 1:25 PM

Subject: ACI 318 Appendix D



O.K., I've beaten my head against the wall long enough. I've decided that a
post-installed anchor won't work in tension for anything I design.



I feel better now.





T. William (Bill) Allen, S.E.

ALLEN DESIGNS

Consulting Structural Engineers
V (949) 248-8588 . F(949) 209-2509