Check eccentric fillet weld, 8 mm, P=100 kN

Basis: working stress method (permissible shear stress in weld 108 N/mm²). The gusset (14 mm) is welded to the column flange by a C-shaped fillet weld: top and bottom 200 mm and vertical 200 mm. $P=100$ kN acts parallel to the flange at $e=400$ mm from the weld plane, giving direct shear and bending. Weld size $s=8$ mm, throat $t_t=0.7\times8=5.6$ mm.

Weld group (per mm of throat)

• $L=2\times200+200=600$ mm
• $I_{xx}=\dfrac{200^3}{12}+2\times200\times100^2=4666667$ mm³
• $M=100\times10^3\times400=40\times10^6$ N·mm

Force per mm of weld at the extreme weld (y = 100 mm)

• Shear: $q_s=\dfrac{P}{L}=\dfrac{100000}{600}=166.7$ N/mm
• Bending: $q_b=\dfrac{My}{I_{xx}}=\dfrac{40\times10^6\times100}{4666667}=857.1$ N/mm
• Resultant $q=\sqrt{q_s^2+q_b^2}=873.2$ N/mm

Stress in the weld

$$\tau=\frac{q}{t_t}=\frac{873.2}{5.6}=155.9\ \text{N/mm}^2>108\ \text{N/mm}^2$$

Answer: the joint is NOT safe (stress is about 156 N/mm² against 108 N/mm² permissible). It needs a larger weld (about 12 mm) or a deeper weld.