As per IS 800: 2007, which type of beam does NOT need a lateral torsional buckling check?

Question

Question

This question was previously asked in

RRB JE CE 22 Apr 2025 Shift 1 CBT 2 Official Paper

Answer 1

Explanation:

As per IS 800: 2007 (General Construction in Steel — Code of Practice):

Lateral Torsional Buckling (LTB) is a stability concern primarily for open sections (like I-beams) when bending about their major axis and the compression flange is unrestrained.
Hollow rectangular or tubular sections are closed shapes and geometrically stable in torsion.
Their symmetry and enclosed shape resist both lateral displacement and twisting, making LTB checks generally unnecessary.

Additional Information

Plate girders: Require LTB checks, especially due to their large depth and slenderness.
Beams bending about their major axis with λLT more than 0.4: Higher slenderness ratio indicates potential for buckling; LTB check is required.
I-section beams with a long span: More susceptible to LTB due to unrestrained compression flange over long lengths.