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GATE 2018 CE (CE1) – Question 19

Concrete Structures · Design and detailing of beams and slabs · 1 mark · Multiple choice

Two rectangular under-reinforced concrete sections X and Y are identical except Y has 10% more longitudinal compression reinforcement. Which is correct?

  1. X has less flexural strength and less ductility than Y
  2. X has less flexural strength but more ductility than Y
  3. X and Y have equal flexural strength but different ductility
  4. X and Y have equal flexural strength and ductility

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Show answer and explanation

Correct answer: (A) X has less flexural strength and less ductility than Y

Explanation

With tension reinforcement unchanged and both sections under-reinforced, increased compression reinforcement mainly reduces neutral-axis depth and improves curvature ductility. The keyed comparison treats flexural strengths as equal but ductilities as different (C), using the conventional under-reinforced approximation.