
116 Forensic Engineering Fundamentals
the pressures are D
1
w and D
2
w. e weight of the water w is taken to be 62.4 lb. e corre-
sponding pressures are then
F
Dw
F
1
1
2
2
2
2
;
(5.7)
e total eective pressure is then
FDD
t
=−
1
2
2
2
(5.8)
e total eective pressure passes through the center of the trapezoid shown in red and is
given by
DD
D
t
=+
+
1
3
1
2
2
(5.9)
For D
1
= 12 and D
2
= 9, D
t
= 5.28.
As another example that is commonly encountered consider a dam structure that is
constructed to retain the water in a pond. e pond experiences a large accumulation of
water runo so that the dam has an overow condition as shown in Figure 5.4.
D
2
D
1
F
H
Water ...