Shear stress in a standard steel shape

Constructing the shear diagram

Considering the segment
from x = 2 m to x = 2 m

     area under load
                diagram =    0.00 kN
         concentrated
                   forces =  -12.00 kN
     total shear force
                  change = -12.00 kN

              at x = 2 m,    V =    -10.00 kN
        total shear force
                     change   =      -12.00 kN
               at x = 2 m,   V =     -22.00 kN