Question

Maximum vertical compressive stress acting at the base of a gravity dam is found to be 240 tonnes per square meter. Sum of vertical and horizontal forces acting on the dam are calculated as 4600 tonnes and 400 tonnes per meter length respectively. If the base width of the dam is 30 m, the resultant force will be acting with an eccentricity of ____

• A. 1.8 m
• B. 2.8 m
• C. 4.3 m
• D. 5.1 m

Answer 1

The correct option is B 2.8 m

Maximum vertical stress,
$P_{max}=\frac{F_v}{B}[1+\frac{6e}{B}]$

$F_v=\text{Sum of vertical forces}=4600t$

e = eccentricity of resultant force

B = Base width = 30 m

$\Rightarrow 240t/m^2=\frac{4600t/m}{30m}[1+\frac{6e}{30}]$

By solving , eccentricity, e = 2.826 m