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Re: Steel Reinforcement Elongation Limit

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Jim, I think the point was that the difference between 58 and 60, or 29 and
30, or 38.7 and 40, is very small (3.3%), and is below the threshold of our
precision with respect to manufacture, placement, and loading.

Your example of concrete strains, Jim, is I hope facetious, since that
example is a difference of 33% instead of 3.3%, which is an order of
magnitude different.  Go back to high school chemistry lab where you learned
that precision up to 3 significant figures is pushing it for that level of
sophistication and equipment.  Now remember that a typical construction
jobsite is at least one if not two orders of magnitude more crude than your
high school chemistry lab.  Are you going to form the concrete and place the
rebar yourself?  Are you going to place the concrete yourself?

29 ksi, 40 ksi, and 60 ksi are used by thousands of engineers.  Let's keep
that consistent.  I do, however, see a need in the evaluation of existing
buildings to make adjustments to these numbers.  Those adjustments, however,
are more crude than 3.3%.

My 2 cents....

Mark Swingle


Jim wrote:

<<Thanks for a good answer....

<< leads me to the question......what
<<value do you utilize for the cracking strain of
<<concrete.... .003 ... .004...  .005.....or is that
<<also irrelevant in our code dominated world..... ??


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