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Re: LRFD, ASD, and USD

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John Cannon Jones wrote:

...What Modern Steel did not mention was the article in Concrete
Construction (concerning composite slabs) mentioning that the concrete
volumes go UP even more than that because of the additional deflection
of the Gr. 50 deck and steel along with the savings from the LRFD method
(as compared to ASD).  Now the slab is thicker and weighs more ....

You are pretty much stuck with the additional deflection in the deck;
however, you can always camber the beams to accomodate the additional
deflection.  I recently had the opportunity to Value Engineer a
structural steel building designed by an old timer.  Utilizing LRFD,
50ksi steel, and AISC floor vibration criteria, we reduced the steel by
40%, using the same beam and girder layout as the original plans.

Brian K. Smith, P.E.