Page 34 - Unit2.docx

Solution

 
2. NA for the raking piles : 4 (0)+2 (0.9) = 6e ⇒ e r = 0.3 m

 
2. NA for the vertical piles: 2 (0)+2 (2) = 4e ⇒ e v = 0.5 m

3. Establish moment arm Y


Inclination 5:2⇒ Y = 5 (0.6+0.5) -0.6 = 4.9 m

∴ M = Q (X) - H(Y) = 3600(0.2) - 200(4.9) = -260 kNm

4. Establish the angle α and the perpendicular distance r, of the piles from the
neutral axis.

slope 5:2 ⇒ α = 22.3°

sinα = 0.296

cos α = 0.98

2α
cos = 0.96
© It's Engg. Life
tanα = 0.20

Raking piles


For raking piles laying on axis a ,


-r i = 0.3 (cos α )


+r i = 0.6 (cos α )

2α
= (0.3 cos )
2 


2 
2
2
∑ r I = (0.3 0.96 ) 4 = 0.346 m

 
For raking piles laying on axis b and b ,
= (0.6 2  cos 2α )

2   2
= (0.6 0.96) 2 (two piles) = 2.037 m

 2
∑ = (0.346+2.037) 2 = 2.07 m

Vertical piles

r i = ± 0.5 m