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Re: ACI 318 - request for comments for improvements

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I am not sure what the "slag mix" you mentioned is, but I would not
advise using it. In California we had "pop out" problems years ago, with
use of Kaiser steel slag as the course aggregate. With regard to your
comments about steel being much more "forgiving material", it sure wasn't
true with regard to the hundreds of welds that broke in the '94 seismic
event. We are still recovering from that. It has caused a complete review
of the design methods, the Codes and much else.

Stan Scholl, P.E.
Laguna Beach, CA 

On Sat, 09 Jun 2001 03:39:53 -0500 Mark Nowmos <mnowmos(--nospam--at)compuserve.com>
writes:
> From a practical standpoint, I would say that there is much more 
> involved with
> designing with concrete than with steel.  Mix designs play a crucial 
> role in
> this, more from the actual placing than in the finished product.  
> I'll give an
> example:  I was recently at a pre-pour conference where the concrete 
> contractor
> expressed concerns about using a slag mix when there are high winds 
> present at
> the time of placing.  This was for a slab-on-grade.  His concern was 
> that the
> wind, temperature, and humidity might cause a slag mix to set 
> prematurely on
> the upper part of the slab, while the lower, unexposed part would 
> set later,
> causing, as he put it, "crusting" of the slab.  Apparently, and I'm 
> not sure if
> this is true, a slag mix will delay the setting of the concrete as 
> opposed to a
> straight Portland cement mix.  I'm assuming this is beneficial to 
> the
> finishers.  Anyway, my point is, with steel, you don't have these 
> problems, it
> is generally a more forgiving material.  You usually get what you 
> expect.
> There is just another consideration you have to address during 
> design that you
> wouldn't with steel.  Granted, my example is one where you couldn't 
> use steel,
> but if it was a multi-story building, it would be a consideration.  
> Using steel
> affords you the luxury of not having to worry about such details.  
> I'm not
> saying that using steel is always better, it just seems to allow for 
> more
> unforeseen problems than concrete, especially if the contractor 
> screws
> something up.
> 
> Mark Nowmos
> 
> "Conrad Guymon, P.E." wrote:
> 
> >
> > I prefer the commentary in the side by side format.  Makes it so 
> you don't
> > have to flip from the code to the commentary and back again to 
> make sense
> > out of it.  Also gives some white space to make notes in.
> >
> > Conrad
> >
> > ----- Original Message -----
> > From: "Lutz, James" <JLUTZ(--nospam--at)earthtech.com>
> > To: <seaint(--nospam--at)seaint.org>
> > Sent: Friday, June 08, 2001 3:21 PM
> > Subject: RE: ACI 318 - request for comments for improvements
> >
> > > When I read your post, I blew the dust off my ACI 318-63 from 
> college days
> > > just to get a feel for whether things were all that different in 
> scope
> > from
> > > 28 years ago. Except for format changes, formula refinements, 
> and the
> > > addition of commentary, I don't think the amount of work 
> involved in
> > > concrete design is radically different from the "good old days." 
> If
> > > anything, the advent of cheap computers, spreadsheets, and 
> affordable
> > > software have made the design (if not the detailing) of concrete 
> easier.
> > >
> > > I think ACI 318 is a pretty good code, and tinkering with it 
> just to try
> > and
> > > make it more "user friendly" isn't going to make concrete any 
> more
> > > attractive.
> > >
> > > If you have any influence with PCA, though, I wish they would 
> provide a
> > > proper index in the back to make it easier to find relevant 
> information in
> > > their "Notes on ACI 318" design publication. I also preferred 
> the earlier
> > > format for printing the Commentary to ACI 318 as a separate 
> section (like
> > > AISC does) rather than side by side with the code itself.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Scott.Maxwell(--nospam--at)aci-int.org 
> [mailto:Scott.Maxwell(--nospam--at)aci-int.org]
> > > Sent: Friday, June 08, 2001 12:15 PM
> > > To: seaint(--nospam--at)seaint.org
> > > Subject: ACI 318 - request for comments for improvements
> > >
> > >
> > > Greetings:
> > >
> > > I would like to see if you would provide us with a little 
> assistance,
> > which
> > > ultimately could end up helping yourself.
> > >
> > > ACI has heard and received comments about the complexity of the 
> ACI 318
> > > concrete code.  Some surveys have suggested that more structural 
> engineers
> > > prefer to design in steel than in concrete.  Some use these 
> surveys to
> > > conclude that the ACI 318 code is a major contributor to this 
> preference.
> > > This concern has been expressed to ACI by several of the major 
> concrete
> > > trade associations.
> > >
> > > We would like to conduct a survey to attempt to determine what 
> areas of
> > the
> > > code need improvement or clarification (note, I hesitate to use 
> the word
> > > "simplification").  The hope is to get some feedback on how to 
> improve the
> > > 318 code to make it more useful and user-friendly.
> > >
> > > We are currently at a loss, however, as to how approach this 
> problem,
> > > especially since the code itself is rather large, making it 
> difficult to
> > > focus in on particular problems.  We are hoping that you might 
> be willing
> > > to offer some ideas.  For example, what areas of the ACI 318 
> code do you
> > > find too complex or burdensome to use?  Basically, we are 
> looking for you
> > > to share with us some of you experiences and thoughts on using 
> this code.
> > > We hope that this will help us craft a more through survey that 
> will allow
> > > us to determine how we can make the ACI 318 code a better, more
> > > user-friendly document.
> > >
> > > Thanks,
> > >
> > > Scott
> > >
> > > _____________________________________________
> > > Scott E. Maxwell, PE, SE
> > > Structural Engineer
> > >
> > > ACI International (American Concrete Institute)
> > > 38800 Country Club Drive
> > > Farmington Hills, MI  48331
> > >
> > > T:  (248) 848-3829
> > > F:  (248) 848-3720
> > > E:  Scott.Maxwell(--nospam--at)aci-int.org
> > >
> > >
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