huangyhg

hs sections
is it true that hs sections don't buckle under compressive loads? and why does that happen?
thank you
ngedm

what are hs sections?
hss or hollow structural steel sections won't buckle locally under compressive loading, they are proportioned to do this; so are most rolled sections. they will, however, buckle over their length, like any other column.
alanr (visitor)30 jul 01 8:11
hs sections are "hollow square" sections
these sections will perform like any other section when acting like a strut. (ie a column)
when under flexure, hs sections will not normally fail under lateral torsional buckling depending upon d/b criteria.
the uk british standard b.s. 5950art 1 : 1990 : appendix b clause b.2.6.1 gives these criteria ( i apologise to all the international contributors to this forum)
i still see a lot of ts8x8x3/16 and 7x7x3/16 columns being used, which according to my calculatons on local buckling criteria table b5.1 of asd are slender elements and therefore allowable stresses should be reduced according to appendix b5. these sections are also absent from the column load table p.3-41 which is based on sections that meet table b5.1 criteria.
dik was right, hss stands for hollow structural sections, not hollow square sections. you can have an hss 12x6x1/2 or the like.
check your fy for tube sections. typically 46 ksi. that might get your tube to be compact.
fy in our environs is 50 ksi... 350mpa... same value for rolled sections... the b/t ratios are such that local buckling is not an issue and they can be compact or non-compact... generally (local) any column over 12' long unless very heavily loaded is hss for economy...
while we're on the topic of hss, has anyone heard of hss twisting? example: the columns were hss5x5x1/4 approx 40'. the contractor said that by the time they were framing beams at the roof level, the columns were twisted out of perpendicular to the base plates. i wonder if because of the thin wall (1/4"), when the fabricator was welding on shear tabs, maybe that put a little twist in it, or if perhaps it was just poor storage/handling at the site. also noteworthy- the contractor did say that not all columns were twisted. any thoughts?
guset (visitor)31 jul 01 11:53
on the subject of hhs tubes, can these be designed as
beams simlar to steel beams, design by asd: sx, or allowable
load. is there any special consideration to taken into account?

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