Question

Non-dimensional slenderness ratio is given by

(a) λLT = √(βbZpfy/Mcr)

(b) λLT = √(βbZpfyMcr)

(c) λLT = √(βbZp/Mcr)

(d) λLT = √(βbZpfy)

I got this question in an international level competition.

I want to ask this question from Design Strength of Laterally Unsupported Beams topic in chapter Design of Beams of Design of Steel Structures

Answer 1

Correct choice is (a) λLT = √(βbZpfy/Mcr)

To explain: Non-dimensional slenderness ratio is given by λLT = √(βbZpfy/Mcr), where βb  = 1 for plastic and compact sections, βb  = Ze/Zp for semi-compact sections, Ze = elastic section modulus, Zp = plastic section modulus, Mcr  is elastic critical moment.