CIVIL WORKS GUIDELINES FOR MICRO-HYDROPOWER IN NEPAL
111
F7
F7 = γwater htotal Π(d+t) t
=31htotal(d+t)t
Usually insignificant
F8
F
8
=
[2Q2/(1/4)
Π
d2]
sin
(β
-
α)/2
= 2.5 (Q2 / d2) sin (β - α)/2
Usually insignificant
F9
F9 = γwater htotalx Π/4(dbig2 - dsmall2)
=7.7htotal(dbig2 - dsmall2)
Uphill portion Downhill portion
F7d
F7u
F8 direction as F3
F7 is the hydrostatic force on bends
that acts along the bisector of the
bend.
Applies to anchor blocks only.
F8 is the dynamic force at a bend due
to change in direction of moving
water. Velocities are usually low in
penstocks so this force is small.
Applies to anchor blocks only.
F9 is the force due to reduction in
pipe diameter from dbig to d small
Applies to anchor blocks only.
F10
F10
=
—γs—2oilh—12
cos i x Ka x w
Wb
W
b
=
Vol.
black
X
γblack
F10 is the force due to soil pressure
upstream of the block.
Applies to both anchor blocks and
support piers
Calculate F10 if (h1 - h2) is more than 1
m. The force acts at 1/3 of the height
(h1) from the base of the block.
Wb is the weight of block.
Applies to anchor blocks and support
piers.