A beam curved in plan is designed for:
Try it first: pick an option, then read the explanation.
Correct answer: D. bending moment, shear and torsion
Asked in SSC JE 22/01/2018 (Evening)
Detailed Explanation
In a straight beam the loads act in the plane of the beam, causing bending and shear only. In a beam curved in plan (a circular balcony beam, a ring beam over columns), the centre of the loaded arc lies off the straight line between the supports.
Why “bending moment, shear and torsion” Is Correct
That eccentricity makes the beam twist about its own axis, so torsion develops in addition to bending moment and shear. All three must be designed for — option (d).
Why the Other Options Are Wrong
- A. bending moment and shear: Misses the torsion caused by the curvature.
- B. bending moment and torsion: Misses the shear, which is always present under transverse load.
- C. shear and torsion: Misses the bending moment, which is usually the largest effect.
Key Point
Beam curved in plan ⇒ bending + shear + torsion.
Key Concepts for Students
- Balcony beams supporting cantilever slabs are a classic case of torsion.
- Torsion in RCC needs closed stirrups and longitudinal bars.
- Ring beams of circular tanks are curved in plan.
Practice more: this is question 35 in Bending Moment and Shear Force MCQs – Part 3. Try the whole set and check every answer instantly.