3. Compare the relative advantages and disadvantages of (driven) precast concrete piles and drilled shafts (cast-in- situ). List the site conditions and structural conditions that favor or hinder the use of these two types of deep foundation. Be as specific as possible. Figure, Tables, and Equations: 7.5.14c (1+0.1952)(1 +0.4%) + D +q (10.11) B Pile: Meyerhof's method Q₁ = 4,9, = Aq'N <≤ Aq₁ q 9₁ = 0.5ptan o' TABLE 12.6 Interpolated Values of N Based on Meyerhof's Theory Soil friction angle, ' (deg) 20 N₁₂ 12.4 21 13.8 Qu(net) qu q = 5.14c 1 + 0.195- = (1 + 0.1954)(1 +0.4%) (10.12) B all(net) qu(net) FS = 1.713c. (1 + 0.1952)(1 + 0.47%) (10.13) B General bearing capacity equation qu= c'NcFcs Fca Fci+q'NqFqsFqaFqi + 0.5yBNy Fys Fya Fyi Shape factors by De Beer Depth factors by Hansen (1970) (1970) Inclination factors by Meyerhof (1963) and Hanna and Meyerhof (1981) BN Fes 1+G Fcd =1+0.4( 0.4 Во = Fei Fai = (1-2)² 90°) 35 222222223136 15.5 17.9 24 21.4 25 26.0 29.5 27 34.0 28 39.7 29 46.5 30 56.7 68.2 81.0 96.0 34 115.0 143.0 168.0 B +tan Fqs = 1 + (+) tan p' Fqd = 1 + 2 tan q' (1 − sin ')² Dr - B Fyi = (1-B 37 194.0 φ 38 231.0 Fys = 1-0.4(+) Fyd = = 1 39 276.0 40 346.0 41 420.0 42 525.0 Shallow foundation: TABLE 6.2 Bearing Capacity Factors From Eqs. (6.30), (6.29), and (6.31) 43 650.0 TABLE 6.2 Bearing Capacity Factors From Eqs. (6.30), (6.29), and (6.31) (Continued) 44 780.0 45 930.0 $' N₁ N₁ Ny $' N₂ No Ny 22 16.88 7.82 7.13 37 55.63 42.92 $' No N₁ Ny $' No Na 66.19 Ny 0 5.14 1.00 0.00 11 8.80 2.71 1.44 27 23 18.05 8.66 8.20 38 61.35 48.93 78.03 24 19.32 9.60 9.44 39 67.87 55.96 92.25 1 5.38 1.09 0.07 12 9.28. 2.97 1.69 25 20.72 10.66 10.88 40 75.31 64.20 109.41 2 5.63 1.20 0.15 13 9.81 3.26 1.97 26 22.25 11.85 12.54 41 83.86 73.90 130.22 3 5.90 1.31 0.24 14 10.37 3.59 2.29 27 23.94 13.20 14.47 42 93.71 85.38 155.55 4 6.19 1.43 0.34 15 10.98 3.94 2.65 28 25.80 14.72 16.72 43 105.11 99.02 186.54 29 27.86 16.44 19.34 44 118.37 115.31 5 6.49 1.57 0.45 16 11.63 4.34 224.64 3.06 30 30.14 18.40 22.40 45 133.88 134.88 271.76 6 6.81 1.72 0.57 17 12.34 4.77 3.53 31 32.67 20.63 25.99 46 152.10 158.51 330.35 7 7.16 1.88 0.71 18 13.10 5.26 4.07 32 35.49 23.18 30.22 47 173.64 187.21 403.67 8 7.53 2.06 0.86 19 13.93 5.80 4.68 33 38.64 26.09 35.19 48 199.26 222.31 496.01 9 7.92 2.25 1.03 20 14.83 6.40 5.39 34 42.16 29.44 41.06 49 229.93 265.51 613.16 10 8.35 2.47 1.22 21 15.82 7.07 6.20 35 46.12 33.30 48.03 50 266.89 319.07 762.89 (continued) 36 50.59 37.75 56.31 The critical depth for skin friction in piles L'≈ 15D The unit frictional resistance or the unit skin friction f = Kσ tan S'

3. Compare the relative advantages and disadvantages of (driven) precast concrete piles and drilled shafts (cast-in- situ). List the site conditions and structural conditions that favor or hinder the use of these two types of deep foundation. Be as specific as possible. Figure, Tables, and Equations: 7.5.14c (1+0.1952)(1 +0.4%) + D +q (10.11) B Pile: Meyerhof's method Q₁ = 4,9, = Aq'N <≤ Aq₁ q 9₁ = 0.5ptan o' TABLE 12.6 Interpolated Values of N Based on Meyerhof's Theory Soil friction angle, ' (deg) 20 N₁₂ 12.4 21 13.8 Qu(net) qu q = 5.14c 1 + 0.195- = (1 + 0.1954)(1 +0.4%) (10.12) B all(net) qu(net) FS = 1.713c. (1 + 0.1952)(1 + 0.47%) (10.13) B General bearing capacity equation qu= c'NcFcs Fca Fci+q'NqFqsFqaFqi + 0.5yBNy Fys Fya Fyi Shape factors by De Beer Depth factors by Hansen (1970) (1970) Inclination factors by Meyerhof (1963) and Hanna and Meyerhof (1981) BN Fes 1+G Fcd =1+0.4( 0.4 Во = Fei Fai = (1-2)² 90°) 35 222222223136 15.5 17.9 24 21.4 25 26.0 29.5 27 34.0 28 39.7 29 46.5 30 56.7 68.2 81.0 96.0 34 115.0 143.0 168.0 B +tan Fqs = 1 + (+) tan p' Fqd = 1 + 2 tan q' (1 − sin ')² Dr - B Fyi = (1-B 37 194.0 φ 38 231.0 Fys = 1-0.4(+) Fyd = = 1 39 276.0 40 346.0 41 420.0 42 525.0 Shallow foundation: TABLE 6.2 Bearing Capacity Factors From Eqs. (6.30), (6.29), and (6.31) 43 650.0 TABLE 6.2 Bearing Capacity Factors From Eqs. (6.30), (6.29), and (6.31) (Continued) 44 780.0 45 930.0 $' N₁ N₁ Ny $' N₂ No Ny 22 16.88 7.82 7.13 37 55.63 42.92 $' No N₁ Ny $' No Na 66.19 Ny 0 5.14 1.00 0.00 11 8.80 2.71 1.44 27 23 18.05 8.66 8.20 38 61.35 48.93 78.03 24 19.32 9.60 9.44 39 67.87 55.96 92.25 1 5.38 1.09 0.07 12 9.28. 2.97 1.69 25 20.72 10.66 10.88 40 75.31 64.20 109.41 2 5.63 1.20 0.15 13 9.81 3.26 1.97 26 22.25 11.85 12.54 41 83.86 73.90 130.22 3 5.90 1.31 0.24 14 10.37 3.59 2.29 27 23.94 13.20 14.47 42 93.71 85.38 155.55 4 6.19 1.43 0.34 15 10.98 3.94 2.65 28 25.80 14.72 16.72 43 105.11 99.02 186.54 29 27.86 16.44 19.34 44 118.37 115.31 5 6.49 1.57 0.45 16 11.63 4.34 224.64 3.06 30 30.14 18.40 22.40 45 133.88 134.88 271.76 6 6.81 1.72 0.57 17 12.34 4.77 3.53 31 32.67 20.63 25.99 46 152.10 158.51 330.35 7 7.16 1.88 0.71 18 13.10 5.26 4.07 32 35.49 23.18 30.22 47 173.64 187.21 403.67 8 7.53 2.06 0.86 19 13.93 5.80 4.68 33 38.64 26.09 35.19 48 199.26 222.31 496.01 9 7.92 2.25 1.03 20 14.83 6.40 5.39 34 42.16 29.44 41.06 49 229.93 265.51 613.16 10 8.35 2.47 1.22 21 15.82 7.07 6.20 35 46.12 33.30 48.03 50 266.89 319.07 762.89 (continued) 36 50.59 37.75 56.31 The critical depth for skin friction in piles L'≈ 15D The unit frictional resistance or the unit skin friction f = Kσ tan S'

Principles of Foundation Engineering (MindTap Course List)

9th Edition

ISBN:9781337705028

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter12: Pile Foundations

Section: Chapter Questions

Problem 12.14P

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