Concept explainers
Find the percentage of load carried by the shaft.
Answer to Problem 13.1P
The percentage of load carried by the shaft is
Explanation of Solution
Given information:
The diameter of the base
The total length (L) is 27.0 ft.
Unit weight of loose sand
Unit weight of dense sand
The diameter of the shaft
The length of the shaft
The value of factor of safety (FOS) is 4.
Consider
Calculation:
Find the area of the base
Substitute
From given Figure, find the effective stress of soil.
Find the ratio
Substitute 27 ft for
Refer Table 13.3. “Berezantzev et al.’s value of
The value of
Find the bearing capacity factor
Substitute
Find the net ultimate load carrying capacity at the base
Substitute
Find the shaft load
Find the perimeter of the shaft
Substitute 2.5 ft for
Find the value of
Substitute
Find the value of
Substitute
Find the critical depth
Substitute 2.5 ft for
The value of critical depth 37.5 ft is more than the length
Find the frictional resistance
At depth
At depth
Substitute 0.485 for K,
Find the load carrying capacity of the shaft
Find the ultimate load
Substitute
Find the allowable load
Substitute
Find the percentage of load carried by the shaft:
Substitute
Therefore, the percentage of load carried by the shaft is
Want to see more full solutions like this?
Chapter 13 Solutions
Principles of Foundation Engineering (MindTap Course List)
- A free-headed drilled shaft is shown in Figure P13.10. Let Qg = 260 kN, Mg = 0, = 17.5 kN/m3, = 35, c' = 0, and Ep = 22 106 kN/m2. Determine a. The ground line deflection, xo b. The maximum bending moment in the drilled shaft c. The maximum tensile stress in the shaft d. The minimum penetration of the shaft needed for this analysisarrow_forwardFigure P13.9 shows a drilled shaft extending into clay shale. Given: qu (clay shale) = 1.81 MN/m2. Considering the socket to be rough, estimate the allowable load-carrying capacity of the drilled shaft. Use FS = 4. Use the Zhang and Einstein procedure.arrow_forwardFor the drilled shaft described in Problem 19.7, estimate the total elastic settlement at working load. Use Eqs. (18.45), (18.47), and (18.48). Assume that Ep = 20 106 kN/m2, s = 0.3, Es = 12 103 kN/m2, = 0.65 and Cp = 0.03. Assume 80% mobilization of skin resistance at working load. (See Part c of Problem 19.7) 19.7 Figure 19.16 shows a drilled shaft without a bell. Here, L1 = 6 m, L2 = 7 m, Ds = 1.5 m, cu(1) = 50 kN/m2, and cu(2) = 75 kN/m2. Find these values: a. The net ultimate point bearing capacity. Use Eqs. (19.23) and (19.24) b. The ultimate skin resistance. Use Eqs. (19.26) and (19.28) c. The working load, Qw (FS = 3) FIG. 19.16arrow_forward
- For the same data given in Problem 13.4, determine the load-carrying capacity of the drilled shaft, limiting the settlement to 10.0 mm. 13.4 Determine the ultimate load-carrying capacity of the drilled shaft shown in Figure P13.4, using the Reese and ONeill (1989) method.arrow_forwardFor the drilled shaft described in Problem 19.7, determine these values: a. The ultimate load-carrying capacity b. The load-carrying capacity for a settlement of 25 mm Use the procedure outlined in Section 19.8. 19.7 Figure 19.16 shows a drilled shaft without a bell. Here, L1 = 6 m, L2 = 7 m, Ds = 1.5 m, cu(1) = 50 kN/m2, and cu(2) = 75 kN/m2. Find these values: a. The net ultimate point bearing capacity. Use Eqs. (19.23) and (19.24) b. The ultimate skin resistance. Use Eqs. (19.26) and (19.28) c. The working load, Qw (FS = 3) FIG. 19.16arrow_forwardA 3 ft diameter straight drilled shaft is shown in Figure P13.7. Determine the load-carrying capacity of the drilled shaft with FS = 3. Take / as 0.8 for the sand.arrow_forward
- Principles of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781337705028Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage LearningFundamentals of Geotechnical Engineering (MindTap...Civil EngineeringISBN:9781305635180Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage LearningPrinciples of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781305081550Author:Braja M. DasPublisher:Cengage Learning
- Principles of Geotechnical Engineering (MindTap C...Civil EngineeringISBN:9781305970939Author:Braja M. Das, Khaled SobhanPublisher:Cengage Learning