Saturday, January 17, 2009

Re: Lateral Stability of a Box Beam ?

If the 2 beams are identical with identical loading, there is no benefit to
simple ties. Unless there is some shear resistance mechanism between the
brace points, the unbraced length for lateral buckling is not reduced and
the ladder simply behaves like 2 tied beams (e.g. Iy1 + Iy2) and they just
displace in unison.

Regards
Paul
--
Paul Ransom, P.Eng.
ph 905 639-9628
fax 905 639-3866
ad026@hwcn.org

> From: "Conrad Harrison" <sch.tectonic@bigpond.com>

> Have you considered providing short bridging members between the two beams:
> to create a kind of ladder, or otherwise similar to battened column. The
> displacement of one beam then becomes tied to the displacement of the other
> and the effective length for lateral buckling is reduced. Could still use
> plywood top and bottom for the bridging/bracing it just doesn't have to be
> continuous box section: unless have an aesthetic reason.

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