Exploring the Concept of Moment Conservation in Structural Engineering

[fanieh]

If the base of a column suddenly turns from fixed to pinned.. the moment (bending) would be redistributed to the top of the column or the beam. Why is that? What is the principle called? Conservation of Moments? Or what?

 

[sophiecentaur]

Not quite sure what you are referring to but I guess it's torsion along a beam (?). The distribution of displacement along the beam will end up as the lowest elastic energy situation - shared along the beam. If one part is twisted more than the adjacent part then the torque will be greater and the adjacent part will be rotated a bit - and so on, down the whole length. I guess the 'principle' you're looking for could be could be Minimal Energy.