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RE: ACI 318 Appendix D

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For this section of the code to apply to seismic UPLIFT is pure stupidity. So the wood shearwall is designed to resist either a maximum wind or seismic load. In the case of Southern California most of the time the seismic load governs so the steel anchors must behave in a ductile manner. So let me get this straight:
 
In order for the steel to act in a ductile manner that means the concrete must fail by the various failure modes per appendix D, which means that the edge distance and other anchor bolt conditions must be adjusted so that the allowable anchorage capacity is greater then the allowable steel tensile capacity???
 
So it seems that this is WAY conservative since the tensile capacity of 5/8" dia A307 grade A steel bolt is about 20k, while the typical uplift for wood shearwalls is anywhere from 1k to 10k(Simpson strong walls).
 
This needs to be addressed and a provision written so that this should not apply to the anchorage of lateral resistive elements.
 
 
 
 
 -----Original Message-----
From: Freeman Tang [mailto:FTang(--nospam--at)gouvisgroup.com]
Sent: Thursday, April 16, 2009 4:04 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 318 Appendix D

Instead of having the anchor rod /bolt head embedded inside the concrete member this rod is run from one side to the opposite side of the concrete member/footing and secured with an bearing plate and heavy hex nut.

Freeman

 

From: Gordon Goodell [mailto:GordonGoodell(--nospam--at)harmonydesigninc.com]
Sent: Thursday, April 16, 2009 3:44 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 318 Appendix D

 

I give up.  What do you mean by a through-bolt for this application?

 

 

thanks,

Gordon Goodell

 

From: Freeman Tang [mailto:FTang(--nospam--at)gouvisgroup.com]
Sent: Thursday, April 16, 2009 3:51 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 318 Appendix D

 

We also use through-bolts for fixing missing holdowns at shear wall ends.  Per Appendix D section 2.2 through bolts are not included.

Freeman Tang

Gouvis Engineering

 

From: Garner, Robert [mailto:rgarner(--nospam--at)moffattnichol.com]
Sent: Thursday, April 16, 2009 2:08 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 318 Appendix D

 

In our office, we through-bolt all our concrete anchors and avoid Appendix D entirely.

 

One engineer in our office has a detail where he attaches the heads of his anchor bolts to chains which are in turn fastened to large chunks of Iron dropped in the bottom of the concrete pour, all to avoid Appendix D.

 

"We don't need no stinkin' Appendix D".

 


From: Bill Allen [mailto:t.w.allen(--nospam--at)cox.net]
Sent: Thursday, April 16, 2009 1:26 PM
To: Seaint
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
 
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