The shear span is defined as the zone where:
Try it first: pick an option, then read the explanation.
Asked in SSC JE 2004
Detailed Explanation
In a beam tested under two-point loading, the beam splits into two kinds of zone: the middle zone between the loads (zero shear, constant moment — pure bending) and the end zones between each support and the nearest load.
Why “shear force is constant” Is Correct
Those end zones have a constant shear force equal to the reaction, and are called shear spans (length a) — option (c). The ratio a/d (shear span to effective depth) governs whether a beam fails in shear or flexure.
Why the Other Options Are Wrong
- A. shear force is zero: Zero shear defines the pure-bending zone, not the shear span.
- B. bending moment is zero: BM is zero only at the supports.
- D. bending moment is constant: Constant BM is the pure-bending zone between the loads.
Key Point
Shear span = zone of constant shear between a support and the nearest load; a/d ratio controls shear behaviour.
Key Concepts for Students
- Deep beams have small a/d and fail by arch action.
- a/d below about 2.5 increases shear strength.
- Two-point loading isolates pure bending in the middle zone.
Practice more: this is question 62 in Bending Moment and Shear Force MCQs – Part 5. Try the whole set and check every answer instantly.