What will be the load carrying capacity (kN) of a group of 6 piles, if the individual load carrying capacity is 150 kN and group efficiency is 75%.

A concrete pile 16 in. 16 in. in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using the a. method [use Eq. (12.61) and Table 12.11] b. method c. method Use R=20 for all clays, which are normally consolidated.

Determine the maximum load that can be allowed on the 450 mm diameter pile shown in Figure 18.36, with a safety factor of 3. Use the a method for computing the shaft friction. FIG. 18.36

Refer to the pile shown in Figure P9.1. Estimate the side resistance Qs by Using Eqs. (9.40) through (9.42). Use K = 1.5 and Coyle and Castello’s method [Eq. (9.44)]

Figure 18.39 shows a 3 5 pile group consisting of 16 concrete piles of 400 mm diameter and 12 m in length. What would be the maximum load that can be allowed on the mat with a factor of safety of 3? The piles have center-to-center spacing of 1200 mm. FIG. 18.39

A driven closed-ended pile, circular in cross section, is shown in Figure P12.7. Calculate the following. The ultimate point load using Meyerhof’s procedure. The ultimate point load using Vesic’s procedure. Take Irr = 50. An approximate ultimate point load on the basis of parts (a) and (b). The ultimate frictional resistance Qs. [Use Eqs. (12.42) through (12.44), and take K = 1.4 and δ′ = 0.6ϕ′.] The allowable load of the pile (use FS = 4).

State whether the following are true or false. a. Load carrying capacities of timber piles are less than those of steel or concrete piles. b. If the load carried by the pile cross section decreases linearly with depth, the frictional resistance per unit remains the same at all depths. c. The point load is mobilized well before the shaft load. d. Soil-pile friction angle can be greater than the friction angle of the soil . e. Bored piles are high displacement piles.

Solve Problem 12.13 using Eqs. (12.59) and (12.60). 12.13 A concrete pile 16 in. × 16 in. in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using the α method [use Eq. (12.61) and Table 12.11] λ method β method Use for all clays, which are normally consolidated.

Consider a 500 mm diameter pile having a length of 18 m in a clay. Given: γ = 20.0 kN/m3 and cu = 60 kN/m2. Determine the maximum allowable load (Qall) with FS = 3. Use the α method and Table 12.11 for determining the skin friction and Eq. (12.20) for determining the point load. Allow a factor of safety of 3. What percentage of the ultimate load is being carried by the pile shaft? Is it a friction pile?

Determine the maximum load that can be allowed on a 500 mm diameter and 18 m long pile driven into a clay where = 20.0 kN/m3 and cu = 60 kN/m2. Use the a method for determining the skin friction. Allow a factor of safety of 3. What percentage of the ultimate load is being carried by the pile shaft?