Question

The ordinate of the uplift pressure at a point is found to be 2.8 m while designing the downstream floor thickness of a weir. If the relative density of concrete is 2.4 then the minimum thickness of the floor to be provided for resisting uplift pressure without accounting safety factor is _______

(a) 1.16 m

(b) 2 m

(c) 0.8 m

(d) 2.8 m

This question was posed to me in semester exam.

I'm obligated to ask this question of Seepage Theories in chapter Seepage Theories and Weirs and Barrages Design of Irrigation Engineering

Answer 1

The correct answer is (b) 2 m

The explanation: D/s floor thickness is given by (Neglecting the factor of safety value = 4/3)

t = h / (G-1) where h = 2.8 m and G = 2.4

t = 2.8 / 1.4 = 2 m.