The direction of x, y and a axes were shown in the highlighted part..
I think it is wrong. For red circled beam, i kinda agree that Moment about x-axis was defined as torsional moment.. While moment about z and y axes are bending moment...
But for blue circled beam, I think that Moment about z...
I was told that for building portal frame, the beam to column connection must be rigid , which means, it has to be fixed , while the column to foundation connection can be either fixed or pinned, am I right ? I couldn't find anything about this online . Pls help