crane runway beam with channel cap on w-beam
 

crane runway beam with channel cap on w-beam
i am trying to select an appropriate w-beam and channel cap for a runway beam that is to support an under running bridge crane. the channel cap is to be on top of the w-beam. i am using the aisc asd code and i am having problems with what value to use for "bf" in formula f1-2. would "bf" be the width of the channel flange or the width of the w-beam flange? am i correct in assuming that "af" in that formula would be the sum of the area of one flange of the w-beam and the area of the web of the channel.
also in section b.5.1, on the check for compact or non-compact section, b/t is compared to 65/sqrt(fy). what value of "b" & "t" should be used in this case with the composite section?
thanks in advance for any help with this problem.
tony billeaud
mechanical engineer
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can you switch to the 13th edition spec.? section f4 is more applicable than the old 89 asd stuff.
as for flange compactness, the compression (top) flange is a stiffened element in this case because it's connected to the channel. using 65/sqrt() is very conservative. the bottom line is that standard w-shapes are almost always compact using 65/sqrt(), so are waaay compact when stiffened.
check the aisc site for an excel spreadsheet to use as a guide for this...
dik