Question

Which of the following is correct?

(a) torsional bracing attached near bottom flange should bend in single curvature

(b) torsional bracing attached near bottom flange should not bend in single curvature

(c) its flexural stiffness should be 4EIb/S

(d) its flexural stiffness should be 6EIb/S

I had been asked this question during a job interview.

This intriguing question comes from Factors affecting Lateral Stability topic in portion Design of Beams of Design of Steel Structures

Answer 1

Right answer is (a) torsional bracing attached near bottom flange should bend in single curvature

The explanation: Torsional bracing attached near bottom flange should bend in single curvature and its flexural stiffness should be 2EI/S, where Ib is moment of inertia of brace, S is spacing between girders.