Which of the following is an INCORRECT statement?
Try it first: pick an option, then read the explanation.
Correct answer: B. A slab is primarily designed for torsion
Asked in SSC JE 15/11/2022 (Shift III)
Detailed Explanation
Check each statement in turn. Three are standard facts; one misdescribes how a common structural element behaves.
Why “A slab is primarily designed for torsion” Is Correct
A slab carries load mainly by bending; its reinforcement is designed for the sagging and hogging moments. Torsion is considered only at special locations such as corners of two-way slabs. So "a slab is primarily designed for torsion" is the incorrect statement.
Why the Other Options Are Wrong
- A. Principal planes are subjected to only normal stress: Correct statement: principal planes carry normal stress only, with zero shear.
- C. Rankine gave the maximum principal stress theory for failure of a material at its elastic limit: Correct statement: Rankine's theory is the maximum principal stress theory.
- D. Buckling is related to lateral deflection of a column: Correct statement: buckling is sudden lateral deflection of a slender compression member.
Key Point
Slabs → bending; principal planes → no shear; Rankine → max principal stress; buckling → lateral deflection.
Key Concepts for Students
- Corner torsion reinforcement is provided in restrained two-way slabs.
- Torsion governs members such as spandrel beams and curved beams.
- Rankine's theory suits brittle materials.
Practice more: this is question 2 in Principal Stress and Principal Planes MCQs – Part 1. Try the whole set and check every answer instantly.