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GATE 2022 CE (CE2) – Question 14

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

Read the following statements relating to flexure of reinforced concrete beams: I. In over-reinforced sections, the failure strain in concrete reaches earlier than the yield strain in steel. II. In under-reinforced sections, steel reaches yielding at a load lower than the load at which the concrete reaches failure strain. III. Over-reinforced beams are recommended in practice as compared to the under-reinforced beams. IV. In balanced sections, the concrete reaches failure strain earlier than the yield strain in tensile steel. Each of the above statements is either True or False. Which one of the following combinations is correct?

  1. I (True), II (True), III (False), IV (False)
  2. I (True), II (True), III (False), IV (True)
  3. I (False), II (False), III (True), IV (False)
  4. I (False), II (True), III (True), IV (False)

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Correct answer: (A) I (True), II (True), III (False), IV (False)

Explanation

An over-reinforced section crushes concrete before its tensile steel yields, making I true. An under-reinforced section yields steel first, making II true and providing warning and ductility.

Therefore under-reinforced sections are preferred: III is false. A balanced section reaches both limiting strains together, so IV is false. **T,T,F,F: A**.