Return to index: [Subject] [Thread] [Date] [Author]

RE: aci 318-02 appendix d

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I did not say that psi6 has anything to do with
thickness.

Which formula implies capacity reduction with
increasing c1?

Rajendran
--- "Lutz, James" <James.Lutz(--nospam--at)earthtech.com> wrote:

> I didn't say "h" wasn't the thickness of the
> concrete, all I was saying is
> that there is something odd about the way capacity
> is reduced when you
> increase c1, when in fact it should be the other way
> around. Psi6 is an
> adjustment factor for a corner condition and has
> nothing to do with
> adjustment for thickness.
> 
> -----Original Message-----
> From: Padmanabhan Rajendran
> [mailto:rakamaka(--nospam--at)yahoo.com]
> Sent: Thursday, May 19, 2005 1:19 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: aci 318-02 appendix d
> 
> 
> 'h' is not the embedment depth. It is the thickness
> of
> concrete. Edge effect is embedded in psi6. If
> c2>1.5c1
> then psi6=1. psi5 accounts for the the eccentricity
> of
> bolt CG in relation to the CG of the foundation
> footprint. If h >=1.5c1 and c2>=1.5c1 Vb is
> proportional to (c1)^1.5. If c1 is large, Vb will be
> large too, meaning that the breakout strength in
> shear
> will not control design.
> 
> I don't see any confusion in using the referenced
> section.
> 
> Rajendran
> 
> 
> --- "Lutz, James" <James.Lutz(--nospam--at)earthtech.com> wrote:
> 
> > Jack, this problem has been driving me nuts since
> > you called me up to talk
> > about it this morning.
> > 
> > We are talking about the breakout strength of an
> > anchor in shear. This is
> > taken as a basic value Vb times a series of
> > reduction factors, Av/Avo, psi6,
> > and psi7 (leave psi5 out of the discussion for
> now,
> > since it's an adjuster
> > for group action). Psi7 is just a constant, so it
> is
> > not relevant to the
> > discussion either, which centers around the
> > equations that include edge
> > distances c1 and c2 in them.
> > 
> > The Vb value is proportional to c1^1.5, with no
> > apparent limit other than
> > the fact that at some point Vs will control
> > capacity.
> > 
> > The Av/Avo value cannot exceed 1.0 and is intended
> > to adjust for the ratio
> > of the actual thickness of the concrete to the
> > maximum of 1.5c1, and for the
> > actual width of the breakout surface versus the
> > maximum of 3c1. Another way
> > to express this is (h/1.5c1)*(width/3c1). As c1
> gets
> > bigger and bigger,
> > Av/Avo reduces to zero pretty quickly irrespective
> > of the other variables,
> > which seems a little counterintuitive to me. You
> > would think that you should
> > only get penalized if c1 gets smaller, not the
> other
> > way around.   
> > 
> > Something about this methodology does not add up. 
> > 
> > 
> > 
> > 
> > -----Original Message-----
> > From: Shapton & Partners
> [mailto:shapton(--nospam--at)nwlink.com]
> > Sent: Wednesday, May 18, 2005 1:13 PM
> > To: seaint(--nospam--at)seaint.org
> > Subject: Re: aci 318-02 appendix d
> > 
> > 
> > David, a little while ago I spoke with Basile
> Rabbat
> > on this issue.  
> > Basically, if c1 = infinity, how can c2 = infinity
> x
> > 1.5 (which would 
> > yield Av/Avo <1)?  This is not the intent.  B.
> > Rabbat recognized the 
> > issue and thought clarification would be coming. 
> It
> > is my understanding 
> > that Hilti has figured this out.  I believe the
> > solution relates to a 
> > concrete thickness of 1.5 x the embedment depth as
> > this is thier 
> > standard with Re-500 anchors. Looking at their
> > tables, you can see that 
> > if c1and , c2 are greater than 1.5 x the
> embedment,
> > Av does not enter 
> > into the pixcture. Sorry for the disorganized
> > response, I am just going 
> > out to a meeting, saw your subject, and wanted to
> > send something that 
> > might initiate further discussion.
> > 
> > Jack Shapton
> > 
> > David Adie wrote:
> > 
> > > shear force parallel to an edge
> > >
> > > D.6.2.1 - footnote c - recognizes the fact that
> c1
> > in psi 6 doesn't 
> > > make sense but equation D-21 includes Vb which
> > still has c1 embedded 
> > > in it.  what value to use when c1 = infinity?
> > >
> > > tia
> > > da
> > >
> > 
> > ******* ****** ******* ******** ******* *******
> > ******* ***
> > *   Read list FAQ at:
> > http://www.seaint.org/list_FAQ.asp
> > * 
> > *   This email was sent to you via Structural
> > Engineers 
> > *   Association of Southern California (SEAOSC)
> > server. To 
> > *   subscribe (no fee) or UnSubscribe, please go
> to:
> > *
> > *   http://www.seaint.org/sealist1.asp
> > *
> > *   Questions to seaint-ad(--nospam--at)seaint.org. Remember,
> any
> > email you 
> > *   send to the list is public domain and may be
> > re-posted 
> > *   without your permission. Make sure you visit
> our
> > web 
> > *   site at: http://www.seaint.org 
> > ******* ****** ****** ****** ******* ****** ******
> > ******** 
> > 
> > 
> > This e-mail is intended to be delivered only to
> the
> > named addressee(s) and
> > may contain information that is confidential and
> > proprietary.  If this
> > information is received by anyone other than the
> > named addressee(s), the
> > recipient(s) should immediately notify the sender
> by
> > e-mail and promptly
> > delete the transmitted material from your computer
> > and server.  In no event
> > shall this material be read, used, stored, or
> > retained by anyone other than
> > the named addressee(s) without the express written
> > consent of the sender or
> > the named addressee(s).
> > 
> > 
> > 
> > ******* ****** ******* ******** ******* *******
> > ******* ***
> > *   Read list FAQ at:
> > http://www.seaint.org/list_FAQ.asp
> > * 
> > *   This email was sent to you via Structural
> > Engineers 
> > *   Association of Southern California (SEAOSC)
> > server. To 
> > *   subscribe (no fee) or UnSubscribe, please go
> to:
> > *
> > *   http://www.seaint.org/sealist1.asp
> > *
> > *   Questions to seaint-ad(--nospam--at)seaint.org. Remember,
> any
> > email you 
> > *   send to the list is public domain and may be
> > re-posted 
> 
=== message truncated ===



		
__________________________________ 
Do you Yahoo!? 
Yahoo! Mail - Find what you need with new enhanced search. 
http://info.mail.yahoo.com/mail_250

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********