In the design of a simply supported beam under a uniformly distributed load:
Try it first: pick an option, then read the explanation.
Correct answer: B. check the section at the centre for bending moment and at the support for shear
Asked in SSC JE 02/03/2017 (Morning)
Detailed Explanation
A section is checked where each effect is critical. For a simply supported beam with a UDL, the moment and the shear peak at different places.
Why “check the section at the centre for bending moment and at the support for shear” Is Correct
The bending moment is greatest at the centre (wL²/8), where the shear is zero; the shear is greatest at the supports (wL/2), where the moment is zero. So check bending at the centre and shear at the support — option (b).
Why the Other Options Are Wrong
- A. check the section at the centre for both bending moment and shear: Shear is zero at the centre — checking it there is pointless.
- C. check at the centre for shear and at the support for bending moment: This is the reverse of where each effect peaks.
- D. None of these: Option (b) is correct.
Key Point
SS beam with UDL: M_max at centre, V_max at supports.
Key Concepts for Students
- IS 456 checks shear at distance d from the face of the support.
- Shear reinforcement is closest near the supports.
- Bending steel is critical at mid-span.
Practice more: this is question 42 in Bending Moment and Shear Force MCQs – Part 3. Try the whole set and check every answer instantly.