RAM Concrete Col Design

Question

I am working through the column design and I have isolated just one load combination to try and verify some results I see for the slenderness issues I am having. I am not, however, able to verify the Cm value. I know that was suppose to be a bug that was fixed with a recent update but I'm not sure how my Cm value is being calculated in this case. I would expect a Cm value of 0.29 not the 0.46 shown in the report. 
 
 ACI 318-19 6.6.4.5.3 Cm = 0.6-0.4(M1/M2)

Karl G · Accepted Answer

The 82.91 k-ft Top Minor Moment that is listed in the report is M2,min calculated from Eq 6.6.4.5.4. That clause states that the calculated end moments can be used to determine Cm. 
 If I uncheck the option to consider moment magnification in RAM Concrete Analysis &ndash; Criteria &ndash; General, re-run the analysis, and check the same column for the isolated load combination, I see the output below in the Column Design Report. These reported moments represent the calculated end moments from the analysis and do not consider M2,min. 
 
 The sign convention used by RAM Concrete Column is shown in the image below, which is taken from Section 4.3.3 in the RAM Concrete Column Manual. Note that when the sign of the top and bottom moment are opposite, the column is in double curvature. 
 
 Using this information, Cm is calculated as follows: 
 M1 = 36.85 
 M2 = -106.47 
 Double Curvature 
 Cm = 0.6 - 0.4*(36.85/106.47) = 0.46

RAM Concrete Col Design

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