Hi, everyone. I was told that when a beam is short, L<=5H, the equation of "Stres=Moment*/2nd moment of initeria" is not valid (how). (where H = deapth of beam ; L is the location of F acting on that beam) Is that ture and is that relate to principle axis? Also if it is ture, why people use the following kind of calculation for Bolt Connection in steel design. Thanks alots of your advise in advance.