For some time now we were aware of the fact that the mills were rolling out
tube sections on the lower end of the wall thickness tolerances. The AISC
black book (hollow structural steel sections) indicates the actual thick
nesses for the TS sections. It appears that the actual thickness is 93% of
the nominal thickness for tubes.
No, here's my question: how many engineers revised their braced frame design
aids to account for the local buckling requirements that limits the wall
thickness to width*sqrt(Fy)/110. Are you aware that we can't use the old
good HSS10x10 in the braced frames at all (it requires the minimum wall
thickness of .66")?
Alexander Sasha Itsekson
INGRAHAM DEJESSE ASSOCIATES INC.
(510) 527-7223 ext. 209