Eccentric loading and weld groups For a weld group resisting an in-plane moment about its centroid, which part of the weld offers the greatest resistance to rotation?

Introduction / Context:
Weld groups under eccentric loads experience a combination of direct shear and torsion (or bending) about the group centroid. The distribution of secondary shear (or bending) due to the moment depends on each weld element’s distance from the centroid.

Given Data / Assumptions:

• Weld group in the plane (e.g., fillet weld rectangle).
• Resultant includes a moment M about the centroid.
• Linear elastic distribution proportional to radius from centroid.

Concept / Approach:
The torsional (or rotational) component of stress is proportional to the distance r from the centroidal axis: q_secondary ∝ M * r / J (for torsion-like distribution). Hence, the weld segments farthest from the centroid carry the largest share of rotational resistance.

Step-by-Step Solution:
Compute centroid of weld group and polar moment J (or equivalent).Secondary shear due to moment: q = M * r / J.Largest r → largest q → elements most distant resist most rotation.

Verification / Alternative check:
Design handbooks and codes distribute eccentric shear to welds in proportion to distance from centroid, confirming the principle.

Why Other Options Are Wrong:
Least distant and centrally located have smaller r and thus smaller contribution. Either end is ambiguous and not necessarily the farthest location from the centroid.

Common Pitfalls:
Ignoring the direct shear component; total weld demand is vector sum of direct and secondary components.

Final Answer:
most distant