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Re: STL - ASTM Mill Specification for Fy=46KSI Tube Steel

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The differences are in the shapes of you HSS.  ASTM A500 specified different
strengths for round structural tubings and shaped (rectangular) structural
tubings:
Round HSS    Fy =42 ksi,   Fu =58 ksi
Shaped HSS   Fy =46 ksi,   Fu =58 ksi

You might have used the values for round HSS for shaped HSS.

If you used the old Tables for your column design you were using the Fy =46
ksi
anyway.  Red AISC manual page 3-37 --- 3-45 are prepared for Fy = 46 ksi.
It is listed in that box at top left hand corner.

By the way, the round HSS is not listed in our old design manuals.  You
can't even find it in the LRFD 2nd edition.  Most of the times we have been
designing our columns based on pipes.  Pipes are usually meeting the
requirement for ASTM A53, Type E or S:
Pipes        Fy =35 ksi.  Fu =60 ksi.

To make our life more difficult from now on is that AISC and Steel Tube
Institute is publishing the new tables for round tubings in their 1997 edition
of "Hollow Structural Sections--Connections Manual."  As HHS round tubes
getting more popular, we need to tell our inspectors to look out for the
source on the round shape.  It could either be a pipe or a tube.  As I said
before, in the new Connections Manual, wall thickness and related
properties has been adjusted to the thinner walls.  You should do it on
your designs.
The weights, however, are not changed.  I suspect that has something to do
with their profit margin.  They have sliped this adjustment in rather quietly.

If you notice that you have lost water pressure on the recent home
remodeling project lately.  Check and see if your plumber installed the HSS
tube instead of regular pipe.  ( ..... I am only kidding ....  no eggs
please!!! )

Respectfully

Sam Chang, SE
Cupertino CA

Take a look of StlShape on the web.



Brent Koch wrote:

> I've been using my 8th Edition AISC Manual (Red) which shows Fy = 42 ksi (Fu = 58 ksi) for A500 Grade B cold formed tube.  Is the minimum yield stress for this material increased to 46 ksi in the 9th edition?
>
> Thanks,
>
> Brent Koch, P.E.
>
> Quoting from "Designing With Structural Tubing" by Dr. Donald R. Sherman,
> Professor of Civil Engineering at the University of Wisconsin-Milwaukee.
>
> "In the U.S. There is only one type that can be realistically obtained:
> cold-formed welded tubing.  The typical HSS product is an A500 Grade B
> with a yield strength of 46 kis and an ultimate strength of 58 ksi."
>
> Reprinted by "Modern Steel Construction" February 1997.
>
> Watch out for the 7% reduction on wall thickness recommended by HSS (Hollow
> Structural Sections).
>
> In my shareware program "StlShape" I have implemented the changes.  Check
> it out if you have the time.  Compare the results with your steel manual.
> It is lower!
>
> Respectfully
>
> Sam Chang, SE
>
> URL for StlShape:  "http://members.tripod.com/~stlshape/index.html";
>
> Can someone tell me quickly what the ASTM Spec number is for common A46 Tube
> Steel (TS6x6x1/4")? Is this ASTM A500?
>
> Thanks
>
> Dennis Wish PE
>
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