Question

The base width of a gravity dam is 30 m of material having a specific gravity of 2.65. The dam is designed as an elementary profile with 80% uplift. The allowable compressive stress of dam material is 2800 $kN/m^2$. The allowable height of the dam will be _______

• A. 40 m
• B. 60 m
• C. 80 m
• D. 100 m

Answer 1

The correct option is A 40 m

As per compressive stress criteria

$H_{max}=\frac{f}{y_w(S_c-C+1)}$

Given, $S_c=2.65,C=0.8,f=2800kN/m^2$

$H_{max}=\frac{2800}{9.81(2.65-0.8+1)}$

$=100.15m$

As per base width criteria

$H_{max}=B\sqrt{S_c-C}$

$=30\sqrt{2.65-0.8}=40.8m$

Hence allowable height of dam = 40.8 m = 40 m