Energy needed to break welding of structural (walkway)

Thank you for your speedy response.

I appreciate that the shear force as indicated by you will help in assessing the critical weight that the welding can withstand before rupturing. I hope you are referring to the following workout.

F = s x A = m x g

where, s = shear stress (1,000 kg/cm2), A = shear area (possibly, 8 mm x 75 mm here), maximum weight that can be wupported = 1,000 x 0.8 x 7.5 = 6,000 kg-wt.

However, if I haven't got the things wrong, some amount of energy would have to be spent to break the welding. The energy would perhaps be double if the running length of the weld is doubled. I am at a loss in how to compute this energy.

One of my friends suggested the following,

E = (sAt)/3

where t = Thickness of the weld

Thus energy becomes = E = (1,000 x 9.8 x 10^4) x (0.008 x 0.075) x 0.008 / 3 = 470 J

Is the above workout okay? The assumption my friend made was - under impulse, if onr-third portion of the weld is ruptured the balance would not require any further energy as the crack will propagate down and break the rest of the weld.