"Referred to the compression flange" in AISC-05
"Referred to the compression flange" in AISC-05
(OP)
In AISC-5, Section H1, Iyc is the "the moment of inertia about the y-axis referred to the compression flange". What does this mean? I know what the moment of inertia is, can calculate it about one axis or another, but don't have a clue what they mean here. It sounds like it would be the moment of inertia about the compression flange, only then the ratio in question, Iyc/Ic, would inherently be larger than 1, rather than between 0.1 and 0.9.
Ideas? Thanks!
Ideas? Thanks!






RE: "Referred to the compression flange" in AISC-05
... where Iyc is the moment of inertia about the y-axis of the compression flange.
Why they thought "referred to" was better than "of" is beyond me.
RE: "Referred to the compression flange" in AISC-05
I'll bet I know why they changed it. That could be interpreted as the moment of inertia of the compression flange area about the y axis, or as the moment of inertia (of the section) about the compression flange's y-axis. Makes me wonder if someone didn't scribble in "referred to?" as a question about what it meant, and it got put into the text.
Thanks!
RE: "Referred to the compression flange" in AISC-05
RE: "Referred to the compression flange" in AISC-05
RE: "Referred to the compression flange" in AISC-05
Iyc = tf*bf^3/12
Which should be close to (but less than) half of Iy for most rolled shapes.
RE: "Referred to the compression flange" in AISC-05