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GATE 2024 CE (CE1) – Question 17

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

The following figure shows the arrangement of formwork for casting a cantilever RC beam.

[Figure: a cantilever RC beam projecting from an RC column, supported from the compacted ground by five props S1 to S5. S1 is the prop nearest the column and S5 is at the free end of the cantilever.]

The correct sequence of removing the Shores/Props is

Diagram for GATE 2024 CE (CE1) question 17
  1. S1→S2→S3→S4→S5
  2. S5→S4→S3→S2→S1
  3. S3→S2→S4→S1→S5
  4. S3→S4→S2→S5→S1

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Show answer and explanation

Correct answer: (B) S5→S4→S3→S2→S1

Explanation

A cantilever carries its load by hogging moment, with the largest moment at the support. The props are therefore removed starting from the free end and moving towards the support, so that the beam takes up its load gradually as a cantilever. The sequence is S5, S4, S3, S2, S1. (For a simply supported beam the props are removed from the middle towards the supports.)