Concrete Column Cm factor
Concrete Column Cm factor
(OP)
If I have a concrete column (non-sway) that I am checking for axial load only (no moments- M1 = 0, M2 = 0) but is tall enough to warrant the slenderness check, what would the Cm factor be? Would it be 0.6 or 1.0?






RE: Concrete Column Cm factor
Personally, I'd probably use a Cm of 1.0. But, I think that M2 minimum equation woudl allow you to justify a Cm of 0.6.
RE: Concrete Column Cm factor
M2 need to be at least Cm*M2_Min !
RE: Concrete Column Cm factor
RE: Concrete Column Cm factor
The ration M1/M2 = 1.0 where M1=M2=M_Min is discutable because of the slab dead load cause slab bending that can reduce the M1/M2 ratio...
To be safe I use Cm=1 & M1/M2 = 1.0 for minimum moment ..but I know that not all engineer aggree with me - they find that too much conservative !
RE: Concrete Column Cm factor
RE: Concrete Column Cm factor
Since, analysis doesn't give you end moments except for code required minimum, I believe, you cannot take advantage of Cm being less than 1.