Calculate the maximum allowable shear force Vmax for the girder. The welded steel girder is having the cross section shown in the figure. It is fabricated of two 300 mm x30 mm flange plates and a 300 mm x 30 mm web plate. The plates are joined by four fillet welds that run continuously at the length of the girder. Each weld has an allowable load in shear of 1000 kN/m.