Tony Bryer
8th May 2008, 04:17 PM
We have had a number of queries in recent weeks (perhaps all emanating from the same checking engineer?) regarding the lateral torsional buckling check in ProSteel 5. This is perhaps because we present it in a slightly different way to BS5950-1:2000.
BS5950 4.3.6.2 requires Mx <= Mb/mLT where Mx is the applied moment, Mb is the buckling resistance moment and mLT the equivalent uniform moment factor.
What we do is to calculate the equivalent uniform moment = Mx.mLT
and check that this is no greater than the buckling resistance moment, Mb
It is the same check as BS5950, it's just that we multiply each side of the BS test by mLT. Personally I do think that our way (brought forward from BS5950-1:1990) is clearer ... but then I would, wouldn't I!
BS5950 4.3.6.2 requires Mx <= Mb/mLT where Mx is the applied moment, Mb is the buckling resistance moment and mLT the equivalent uniform moment factor.
What we do is to calculate the equivalent uniform moment = Mx.mLT
and check that this is no greater than the buckling resistance moment, Mb
It is the same check as BS5950, it's just that we multiply each side of the BS test by mLT. Personally I do think that our way (brought forward from BS5950-1:1990) is clearer ... but then I would, wouldn't I!