huangyhg

eccentrically loaded wide flange
carrying a roof truss, i have a w16x40 carrying a uniform load of 2.4 kips for a span of 21'-0". the roof truss bears one the bottom flange, or perhaps i can run spec hangers to carry the trusses from the top flange of the w-section however, how do i go about sizing this steel beam taking the eccentric loading into cosideration. the w16x40 was based on a concentric load. thanks in advance.
kevin
find a job or post a job opening
go for the hanger over the top - sold by simpson and usp. or i have bolted 2x10's or 2x12's to the web and then hung trusses from there. you can add some bracing back to the trusses to "kill" any torque - say 4-6' on center. or tie the beam to another part of the structure.
i am assuming wood trusses
well loading the bottom flange is a more stable condition provided the top flange is still braced. is your top flange braced? the strength looks like you assumed it is.
as far as the torsional design goes, look at aisc's design guide on torsion. is it loaded from both sides?
unfortunately it's only loaded from one side with no bracing back. i'm looking into using a tube shape with bolted connections to the column to prevent any rotation, instead of a w shape sitting on a column. i have a 'wc' of 997 and can't seem to find a tube chart that uses 'wc'. is thee such a thing? thanks again.
kevin
i agree that a tube would be your best bet with torsion with no bracing. you beat me to it.
mike mccann
mmc engineering

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