Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

lateral drift

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I recently designed a trellis using a cantilevered
column lateral resisting system.  I seems that
deflection always controls on these type structures
when trying to abide by allowable lateral drift.  (0.005h)
First, is this what should be used for wind as well
as seismic lateral drift?  Secondly, because the low stresses
and the type of structure involved is it acceptable to
allow much more than this?  At what point does the amount
of deflection render the predicted stresses in substantial
error (with formulas using the assumption of small deflections)?
I have seen steel building manufacturers use allowable drifts
as much as L/100.  Where do they get that?  (by the way the
trellis involved utilized tube steel - OK HSS to be precise -
and the wall thickness would be 1/4" by stress/column analysis
and nearly 1/2" to meet the 0.005h requirement)

Mark Pemberton, P.E.