Cw for a solid rectangular bar

[ajk1]

Is the value of Cw for a solid rectangular bar zero?

 

[KootK]

It's close enough to zero that it's usually taken as zero I think.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[Trenno]

Just for clarification... Cw is the warping constant right?

It's called up as Iw in Australian codes.

 

[jrbaus]

If we are talking about the warping constant, then I believe it is usually neglected for closed sections (or in your case solid sections) since the warping constant is usually quite small relative to the torsion constant "J". The same is not true for open sections, where both the warping constant and torsion constant are used to determine the member (buckling) capacity of beams subject to bending.

Similar to Trenno, my experience is with Australian codes only.

 

[ajk1]

Cw is defined in the Canadian Standard CSA S16.1 as the "warping torsional constant" and is used in the formula for the critical elastic moment of an unbraced member, when computing the resisting moment of a laterally unsupported member.

 

[Trenno]

I recently designed a flat plate to act as a beam (about it's major axis). In regards to finding the member capacity, I assumed Iw = 0 in the following equation.

 

[ajk1]

From where is that equation taken?
If you assume Iw=0, that is the same as assuming Cw=0 in the CSA S16 equation.

 

[jrbaus]

That equation is taken from the Australian Standard for steel structures: AS 4100-1998.

Any chance we can see an extract from CSA S16 showing how "Cw" is used? I can only assume the result will be similar.

 

[Trenno]

Sorry - yes as jrbaus stated, that extract is from AS4100.

 

[ajk1]

ok, thanks. When I get into the office I will scan the page and post it. (we had a bit of snow overnight, so it will be slow drive to work...guess you don't have that problem in Australia...my niece lives in Sydney)

 

[ajk1]

Attached is excerpt from CSA S16-01. I have a feeling that you cannot open the attached...since I cannot open it, but please let me know.