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RE: The 13th Ed. of AISC Manual

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Gary,

I believe that you are correct.  I believe that there is only one "flavor"
of SI and it is consistant in it use of which units to use for certain
situations.  It is then metric which has multiple "flavors", one of which
being SI.

I believe, however, that SI does not "deal" with rebar size/designations.
Thus, even if one "standardizes" on SI (which not everyone has), there is
not a standardization of rebar sizing/designation in metric systems.  I
know of at least two different systems, but I believe that there is three.

The point is that if we (the US) were to get the "SI metric thing back on
track", which "flavor" should we use?  Do we use what Canada uses?  Or
what some in other locations use?  No matter what we choose, we will still
be "in conflict" with someone, especially in things like rebar
size/designation.

FWIW, there are some industries in the US that have been "metrified".  The
auto industry is a reasonably good example.  If you have a "Big Three"
car, try finding a bolt head or nut on it that is sizes for Imperial unit
tools.  Good luck.  To my knowledge, most US cars use metric/SI bolts.
The lugs on my tires require a lug wrench in mm not inches.  I believe
this is because such parts are supplied from both US and non-US suppliers
alike and the products will be sold in the US and abroad.  In the case of
buildings and building materials, then I am designing something that will
largely be supplied (with the possible exception of the raw steel
members), fabricated, built, etc here in the US.  Thus, I will be dealing
with a "closed" system.  The except to some degree is Canada.  Some of our
"raw" materials (i.e. lumber and other wood products) comes from Canada
and potentially some of our designed will be built in Canada.

Regards,

Scott
Adrian, MI


On Wed, 21 Dec 2005, Gary Hodgson & Associates wrote:

> Scott,
>   I may be wrong but I think there are several flavours
> of metric of which SI is only one but it is consistent.
>   I just came back from Great Britain where they are
> more into metric but I noticed that a lot of road signs
> are still in miles.  Engineering on the other hand seems
> to be 100% metric.  I also noticed that they use a
> shiney structural bolt which really stands out and they
> are easy to count from a distance.  And they certainly
> cut a lot of holes in beams for services ahead of time--
> I think to save space between floors.  Any body else
> have any comments on this?
> Gary
> that space is at a premium
>
>
> On 20 Dec 2005 at 23:40, Scott Maxwell wrote:
>
> > Ah, when it comes to concrete, which SI metric do you want? <grin>
> > There are several "flavors" to choose from which mainly effect rebar
> > sizes and size designations.  This is why ACI has such a tough time
> > coming up with an official "metricfication" (real word? if so,
> > spelling?) policy for doing their dual units in their publications (I
> > believe that ACI's official policy is that all ACI documents are
> > supposed to be published in dual units...i.e. Imperial [foot, inch,
> > etc] and SI/metric).  Beyond the issue of rebar, there still needs to
> > be a consensus of what are the official metric units to use in various
> > situations so that we all use the same stuff (not that it is that hard
> > to move between various metric magnitudes).  For example, if you do a
> > cross section of a concrete beam, do you use mm, cm, or m for the
> > linear dimensions?  Some folks like mm while others prefer cm.
> >
> > So getting the "SI metric thing back on track" ain't such an easy
> > thing...and that is not even starting to talk about getting
> > entrenched, old fart dogs (which includes me at this point more than
> > likely) to learn new tricks!  <grin>
> >
> > Regards,
> >
> > Scott (who technically works for a Canadian company now who is forced
> > to do it "our" [i.e. Imperial units] way since they sell/work a LOT in
> > the US <grin> ah, the power to be unilateralists!!!! <grin>) Adrian,
> > MI
> >
> >
> > On Tue, 20 Dec 2005, Paul Ransom wrote:
> >
> > >
> > > Personally, I'm glad to see it. Now if you folks could get the SI
> > > metric thing back on track ...
> > >
> > > --
> > > R. Paul Ransom, P. Eng.
> > > Civil/Structural/Project/International
> > > Burlington, Ontario, Canada
> > > <mailto:ado26(--nospam--at)hwcn.org> <http://www.hwcn.org/~ad026/civil.html>
> > >
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