Question

The value of φLT in bending stress reduction factor is given by

(a) φLT  = [ 1 – αLT (λLT + 0.2) + λ^2LT].

(b) φLT  = [ 1 + αLT (λLT – 0.2) + λ^2LT].

(c) φLT  = 0.5 [ 1 – αLT (λLT + 0.2) + λ^2LT].

(d) φLT  = 0.5 [ 1 + αLT (λLT – 0.2) + λ^2LT].

I had been asked this question during an interview.

Question is taken from Design Strength of Laterally Unsupported Beams in division Design of Beams of Design of Steel Structures

Answer 1

The correct answer is (d) φLT  = 0.5 [ 1 + αLT (λLT – 0.2) + λ^2LT].

Easiest explanation: The value of φLT in bending stress reduction factor is given by φLT  = 0.5 [ 1 + αLT (λLT – 0.2) + λ^2LT], where αLT  is imperfection factor, λLT is non dimensional slenderness ratio.