Sxc in AISC360-05/10 1

[VH1984]

Hi Everyone:

I was designing some I shaped beams when I came across the term Sxc in section F4 of the code, the term is defined as "Elastic section modulus referred to compression flange" much like Iyc in this topic.

However, I'm not sure Sxc can be interpreted the same way as Iyc (which was clarified in the 2010 version of AISC360).

Does anyone know what they mean by this term?

Thanks!

 

[JAE]

When you have a shape that has a neutral axis that is not at the midheight of the shape, then the value of S (equal to I/y) are different for the top and bottom of the shape.

An example of a shape like this would be where you might have a wide flange with a wider top flange than the bottom flange.

The neutral axis would be raised a bit. The value of y(top) would be smaller than y(bottom) and thus you have an Sx(top) and an Sx(bottom) that are different values.
The Sxc refers to the particular flange in compression.

 

[VH1984]

Thanks JAE for your answer, I'm glad it's as simple as that!

Regards.