Vertical face dam
In above fig.9.a shows
section of dam. Fig.9.b shows water pressure distribution diagram. Fig.9.c
shows plan for unit width.
Let,
a = top width of dam;
b = bottom width of
dam;
H = height of dam;
h = height of water
level;
ρw = density
of water;
ρm = density
of dam masonry;
W = self-weight of dam;
P = force due to water;
R = resultant force of
water force and self-weight;
e = eccentricity due to
resultant force;
Now,
we know that resultant stress
 \times 1)
 \times 1 \times \rho_{m})
Where, AD = AC + CD
centroidal distance form vertical face contact with water
To find CD take moment at D
-\left( W \times CD \right)=0)
Where,
P = water force;
P = Area of water pressure diagram (as shown in fig.9.b) X force applied on area
 \times \left( h \times 1 \right))
h = height of water level;
W = self-weight of dam;
Here ‘d’ is unit length = 1
By putting all these values we can find min and max stresses.
First discuss about direct stress σ0 which is developed by total
downward force i.e. self-weight of dam.
We know that
(Note=Total downward force = W)
Where,
A = Base area of dam;
W = Self-weight;
W = Volume X density of dam masonry
Here volume is found
for unit length of dam.
Volume = Cross sectional area X unit length
A = Base area
A = bottom width of dam X unit length;
A = b X 1 = b
Now, discuss about bending stress σb which is developed by wind pressure.
We know that
Here,
W = self weight;
e = eccentricity due to resultant force;
e = eccentricity due to resultant force;
Where, AD = AC + CD
centroidal distance form vertical face contact with water
To find CD take moment at D
Where,
P = water force;
P = Area of water pressure diagram (as shown in fig.9.b) X force applied on area
h = height of water level;
W = self-weight of dam;
Here ‘d’ is unit length = 1
By putting all these values we can find min and max stresses.
1 comments
do (e) has limitation in value?
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