Good day,
I performed a concrete design in STAAD Pro using the moment magnification method, however, there seems to be an error as the Slenderness ratio (Klu/r) reported by STAAD is much smaller than expected. For example, Klu/r reported for Column no.15 is 2.4, however, using hand calculations the value I obtained was 38, which is greater than the limit of 22 for sway frames (hand calculations based on the following values, which can be derived from the model - k (effective length factor)=1 (default), lu(effective length) = 2.875m and r (radius of gyration)=0.25*.3m=0.075m).
Based on the results of the analysis, it appears the moment magnification was neglected as the slenderness ratio produced by STAAD is below the limit set for sway frames. Can anyone provide assistance or clarification as it relates to this issue. I have attached the STAAD file for this issue.
Thanks
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