huangyhg

built-up beam column design
does anyone know of a reference for the design of built up sections acting as beam columns? the section i am dealing with is an endpost of a portal frame on a truss bridge and is singly symmetric with single lacing along the bottom.
vod
the canadian steel code s16.1 has a fair amount of design information for beam-columns...
hi dik,
from my familiarity with the csa s16.1, it does not have formulae for monosymmetric built-up beam-columns. in addition the applied moment is out of plane (weak axis).
regards
vod
treat as class 4 sections...
bs 5950 can be used for designing columns. if the column isn't symmetric then you'd have to calculate its properties, ixx, etc, and centroid and work out your loads as direct and bending if the load was not applied through its centroid and/or if a moment was being applied, checking for buckling as well as against design stress limits. there should also be a bridge code, bs 5400, i think.
vod... my apologies, that was too quick an answer. to explain:
i usually treat members that are class 2 or 3 as class 4 for biaxial bending. this has been limited to non symmetrical cruciform sections created by splitting a w section and welding it to the flange of another w section, but not at the centreline and to t sections created by using two w sections with a second, but smaller 'web' plate.
s16 requires that for monosymmetric shapes that a rational approach be used and suggest the structural stability research design guide be used.
i've treated columns as above by using the reduced loadings afforded by class 4 with the b/t ratios afforded by class 3 or better (this accommodates local buckling of the section elements) in addition, the intersecting member from a stability point is better than having no
thanks for your help.
regards
vod

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