09-24-2010, 09:02 AM
My reason for this is the following: the beam has gravity loads, which means that the bending moment diagram can't have single curvature bending moment, so the shear force can't be large in the middle of the beam where the stirrups are placed at smaller distance. But, for the columns a single curvature bending moment diagram (without change of sign of bending moment) is possible, so the shear force can be large in the middle of the column, where the stirrups are not placed at the same distance as in the plastic hinge region.