DESIGN OF CANTILEVER TYPE SHEET PILE WALL PENETRATING SAND

Enter the value of the angle of shearing resistance of sand (f) degrees Enter the value of the dry unit weight of sand (gd) lb/ft3 Enter the value of the saturated unit weight of sand (gsat) lb/ft3 Enter the sheet pile depth to sea level (L1) ft Enter the sheet pile depth from sea level to dredge line (L2) ft the value of the effective unit weight of sand gsub = gsat - (gw = 62.4 lb/ft3) = lb/ft3 coefficient of active earth pressure (Ka) = (1 - sin f) / (1 + sin f) = coefficient of passive earth pressure (Kp) = (1 + sin f) / (1 - sin f) =

pressure P₁ = g_d L₁ K_a = psf

pressure P₂ = (g_d L₁ + g_sub L₂) K_a = psf

distance L₃ = P₂ / [g_sub (K_p - K_a)] = ft

force F₁ = P₁ L₁ / 2 = kip/ft

force F₂ = P₁ L₂ = kip/ft

force F₃ = (P₂ - P₁) L₂ / 2 = kip/ft

force F₄ = P₂ L₃ / 2 = kip/ft

force F = F₁ + F₂ + F₃ + F₄ = kip/ft

distance d = [F₁ (L₁ / 3 + L₂ + L₃) + F₂ (L₂ / 2 + L₃) + F₃ (L₂ / 3 + L₃) + F₄ (2 L₃ / 3)] / F = ft

pressure P₅ = (g_d L₁ + g_sub L₂) K_p + g_sub L₃ (K_p - K_a) = psf

coefficient A₁ = P₅ / [g_sub (K_p - K_a)] =

coefficient A₂ = 8 F / [g_sub (K_p - K_a)] =

coefficient A₃ = 6 F [2 d g_sub (K_p - K_a) + P₅] / [(g_sub)² (K_p - K_a)²] =

coefficient A₄ = F (6 d P₅ + 4 F) / [(g_sub)² (K_p - K_a)²] =

To find the length L₄, the following equation must satisfy

(L₄)⁴ + A₁ (L₄)³ - A₂ (L₄)² - A₃ L₄ - A₄ = 0

Enter a trial value for the length L₄ ft

the right hand side (RHS) of the above L₄ equation , if different from zero, assume a new trial value for L₄, enter in the box in the previous step and calculate RHS again. Repeat these steps until RHS matches zero.

the theoretical depth of sheet pile D = L₃ + L₄ = ft

the actual depth of sheet pile D_act = 1.3 D = ft

the total height of sheet pile L₁ + L₂ + D_act = ft

Calculation of maximum moment and section modulus

distance of plane of zero shear Z' = [2 F / g_sub (K_p - K_a)]^1/2 = ft

maximum moment M_max = F (d + Z') - [g_sub (K_p - K_a) / 6] (Z')³ = kip.ft

Enter, from Table above, the allowable flexural stress of the sheet pile material s_all = kip/ft²

section modulus of sheet pile S = M_max / s_all = ft³/ft of wall

Summary of Design

Angle of shearing resistance of sand (f) degrees

Dry unit weight of sand (g_d) lb/ft³

Saturated unit weight of sand (g_sat) lb/ft³

Depth to sea level (L₁) ft

Depth from sea level to dredge line (L₂) ft

Theoretical depth of sheet pile D = ft

Actual depth of sheet pile D_act = ft

Total height of sheet pile L₁ + L₂ + D_act = ft

Maximum moment M_max = kip.ft

Allowable flexural stress of the sheet pile material s_all = kip/ft²

Section modulus of sheet pile S = ft³/ft of wall

Copyright 2007-2024 A. Ghaly. All rights reserved. Contact A. Ghaly at ghalya@union.edu

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Disclaimer: The author disclaims any and all responsibility for the application of stated principles, and shall not be liable for any loss or damage arising therefrom.