The following two figure show welded joints (XXX indicated welds), for the same load and same dimensions of plate and weld.
The joint shown in
(a) Fig.I is better because the weld is in shear and the principal stress in the weld is not in line with P.
(b) Fig.I is better because the load transfer from the tie bar to the plate is not direct
(c) Fig.II is better because the weld is in tension and safe stress of weld in tension is greater than that in shear
(d) Fig. II is better because it has less stress concentration