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GATE 2026 CE (CE2) – Question 14

Concrete Structures · Working stress and limit state design concepts · 1 mark · Multiple choice

A rectangular singly reinforced concrete beam has a width of 300 mm and an effective depth of 550 mm. The grades of steel and concrete are Fe500 and M25, respectively. The area of steel in tension is 1963 mm$^2$. The depth of neutral axis is 302 mm. The ratio of the limiting depth of the neutral axis ($x_{u,max}$) to the effective depth ($d$) of the beam is 0.456.

The most probable mode of failure of the beam is

  1. compression failure
  2. bond failure
  3. shear failure
  4. ductile failure

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Show answer and explanation

Correct answer: (A) compression failure

Explanation

The limiting neutral axis depth is $x_{u,max} = 0.456 \times 550 = 250.8$ mm. The actual neutral axis depth of 302 mm is larger, so the section is over-reinforced. Concrete in compression crushes before the steel yields, which is a sudden compression failure.