Steel Deck: Sp & Sn = Sx?

[jopalu]

Refering to a Vulcraft Steel Roof and Floor Deck catalog/design guide, the section properties list values for "Sp" and "Sn". Are these values equivalent to the Section Modulus about the X-X axis?

Please advise ...

 

[WillisV]

Yes - Sp from neutral axis to the bottom and Sn from neutral axis to the top. Should be very close to identical for typical deck profiles.

 

[miecz]

It would be best to ask Vulcraft. I've always taken Sp to be the section modulus per foot of deck width in positive bending (i.e. top of deck in compression), Sn for negative bending.