D1.L.4.1.5 Combined Interaction Check
Members subjected to both axial compression and bending stresses are proportioned to satisfy
when fa/Fa > 0.15, otherwise
It should be noted that during code checking or member selection, if fa/Fa exceeds unity, the program does not compute the second and third part of the formula, because this would result in a misleadingly liberal ratio. The value of the coefficient Cm is taken as 0.85 for side-sway and 0.6 - 0.4·(M1/M2), but not less than 0.4 for no side-sway.
Members subjected to both axial tension and bending stress are proportioned to satisfy