GATE 2024 CE (CE2) – Question 34
A reinforced concrete pile of 10 m length and 0.7 m diameter is embedded in a saturated pure clay with unit cohesion of 50 kPa. If the adhesion factor is 0.5, the net ultimate uplift pullout capacity (in kN) of the pile is _________________ (rounded off to the nearest integer).
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Correct answer: 550
Explanation
The uplift capacity comes from the skin friction (adhesion) along the shaft: $Q_u = \alpha c\pi dL = 0.5 \times 50 \times \pi \times 0.7 \times 10 = 549.8$ kN, about 550 kN. The self-weight of the pile is not counted, as the question asks for the net pullout capacity from the soil.