Sheet Piles Design The Following steps are involved in designing the sheet piles: 1. For each the section shown in figure (2) determines the maximum bending moment. 2. Determine the maximum value of the maximum bending moments (Mmax). 3. Obtain the required section modulus of sheet piles. 4. Choose a sheet pile having a section modulus greater than or equal to the required section modulus from a table. The pit to be constructing as dimension show in the fig (1) From Fig (2) & Fig (3) The active earth pressure is Pa Pa = 0.65 X γs X H X Ka =0.65 X18 X5.2 X0.333 = 02.02 KN/m Where γs Soil density = 18KN/m2 Φ Angle of friction = 320 Ka is the coefficient of active earth pressure Ka = tan² (45 – Φ/2) = tan² (45 – 32/2) =0.333 From Fig (5) Ʃ M B1=0 A= Pa X L1 X (L1/2) = 02.02 X 4.66 X(4.66/2) = 69.61 KN 3.16 3.16 B1 = Pa X L1 –A = 02.02 X 4.66 – 69.61 = 24.8 KN The strut load, from Fig (1) & Fig (2) at A PA = A X a = 69.61 X3.16 = 219.96 KN at B PB = B X a = 24.8 X 3.16 = 78.37 KN To determine the sheet pile section see the load diagram for shear force based on the load diagram, Fig (A.( X1 =(3.16- X1)*30.39 X2 = 1.74 Then, the moments are at A MA = 0.5 X 20.26 X 1.5 X 1.5 = 22.79 KN.m at X1 MX1 = 3.16 X 20.26 X 3.16/8= 25.29 KN.m so S = M max σ all S = 25.29 X 100 /150 = 16.86 m³ Where σ all is the allowable stress of sheet piles = 150 Kg/m² The type of sheet pile use is JFESP-3 (see table of U-Shaped Steel Sheet Pile) The section modulus of sheet pile calculated is less than the selected type of sheet pile (16.86 m³ < 223 m³) To determine the H beam sheet pile For the wale at level A At A M max = A (a)² = 20.26 X (5.5)² = 00.22 Kn.m 0 0 At X1 Mx1= pa (b)² =20.26 X (3.16)² = 25.29 Kn.m 8 8 SH = M max = 25.29 X 100 = 27.19 m³ σ all 93 Where is the allowable stress of H beam sheet piles = 93 Kg/m The type of H beam sheet pile use is 300 X 300 (see table of H beam Steel Sheet Pile) The section modulus of H beam sheet pile selected is greater than the calculated of H beam sheet pile.
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