AISC Table 1-1 3

[Bobby46]

I was curious if anyone knows the reason that AISC Table 1-1 has multiple sections for an individual beam size. Is it to signify some strength difference or availability?

For example: W36 are listed in two "groups". There is a grouping of W36x135 to W36x256 and a separate grouping for W36x231 to W36x652 on the same page

 

[Lomarandil]

Beams in Table 1-1 are classed by the distance between the rollers (inside corners). I'm sure my terminology is a bit off, but that's the gist. Not having my manual in front of me, I think some beam sizes are also then grouped by flange widths.

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just call me Lo.

 

[strucbells]

Lomarandil is correct..it's geometry-driven

 

[SteelPE]

I always thought the grouping was by flange width. At least that's the way it is for the smaller sections. Can't say I venture into the larger (30"+) that often.

For example, if I'm designing a W10x33 beam column and I'm having a terrible time with lateral torsional buckling I know I might be best to go to a W10x49 as that is the next section with a wider flange.

 

[dauwerda]

Lomarandil is correct, they are grouped by distance between the inside of the flanges which is determined by roller width at the mill. Each beam in the set simply has the outside rollers moved in or out to change the flange thickness:

This also correlates to the flange width however it is not a direct correlation - each group the flange width varies some, but take a look at the "T" distance (roller width) and you will see that they are all the same for each group

 

[Bobby46]

Thank you!