Question

Simple bending takes place if

(a) loading passes above shear centre for single symmetric open section

(b) loading passes below shear centre for single symmetric open section

(c) loading plane coincides with one of the principal planes of doubly symmetric section

(d) loading plane do not coincide with one of the principal planes of doubly symmetric section

The question was asked during an online interview.

Origin of the question is Introduction to Beams in division Design of Beams of Design of Steel Structures

Answer 1

Right choice is (c) loading plane coincides with one of the principal planes of doubly symmetric section

To explain I would say: Simple bending takes place if loading plane coincides with one of the principal planes of doubly symmetric section such as I-section or in case of singly symmetric open section such as channel section, the loading passes through shear centre and is parallel to the principal plane. Unsymmetrical bending occurs if loading does not pass through shear centre.