Calculate weld joint maximum load capacity from weld length, throat thickness, and allowable stress.
Throat thickness is the minimum distance from the root of a fillet weld to its face. For a standard 45° fillet weld, throat = leg size × 0.707. It determines the weld's cross-sectional area and load capacity.
For structural steel fillet welds (E70 electrode), allowable shear stress is typically 0.30 × 70 ksi = 21 ksi (145 MPa). Always verify with applicable codes: AWS D1.1 for structural, ASME for pressure vessels.