ABSTRACT
From Eq. (20.28), The expression for D is C1 D2 + C2 D + C3 = 0 where C1 = 2 qu = 60
C2 = - 2 P = -2 x 40 = - 80
Substituting and simplifying 60 D 2 - 80 D - 1253 = 0 or D2 - 1.33 D - 21 = 0 Solving D ~ 5.3 m. Increasing by 40% we have D (design) = 1.4(5.3) = 7.42 m
P=40kN
5.3m
Figure Ex. 20.6
