Where is the effective throat measured for shearing forces of a PJP groove weld reinforced with a fillet weld?

• A. The length of the fillet
• B. The shortest distance between groove root and fillet surface
• C. The thickness of the base metal
• D. The distance from surface to root at the far end

Answer: (B)

The amount of weld that resists shear is governed by the effective throat, which is the smallest cross‑section through which shear flows. In a groove weld that is reinforced with a fillet, this throat is defined by the shortest distance from the groove root to the surface of the fillet reinforcement. This dimension determines the actual shear resistance, because any path larger than this shortest distance won’t control the weld’s capacity. The other dimensions (the fillet length, base metal thickness, or the distance from surface to root at the far end) don’t set the limiting cross‑section for shear.