Questions and Answers of Principles Foundation Engineering

A steel pile (H-section; HP 310 × 125; see Table 12.1a) is driven into a layer of sandstone. The length of the pile is 25 m. Following are the properties of the sandstone: unconfined compression
A 20 m long bored concrete pile having a diameter of 350 mm is load tested, and the data are given below: Also given: Econcrete = 25 × 103 MN/m2.a. Estimate the allowable pile load using
The average values of the undrained shear strength (cu) with depth are given as follows:Depth (m) ……………. cu (kN/m2)0–3 …………………………….. 203–8
Consider a continuous flight auger pile in a sandy soil deposit 10 m long with a diameter of 0.45 m. Following is the variation of standard penetration resistance values (N60) with depth.Depth (m)
Solve Problem 12.13 using Eq. (12.58).Problem 12.13A concrete pile 406 mm × 406 mm in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using thea. α
Solve Problem 12.13 using Eqs. (12.59) and (12.60).Problem 12.13A concrete pile 406 mm × 406 mm in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using
A concrete pile 20 m long having a cross section of 0.46 m × 0.46 m is fully embedded in a saturated clay layer. For the clay, given: γsat = 18 kN/m3, ϕ = 0, and cu = 80 kN/m2.Determine the
A concrete pile 406 mm × 406 mm in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using thea. α method [use Eq. (12.61) and Table 12.11]b. λ methodc.
Redo Problem 12.10 using the l method for estimating the skin friction and Meyerhof’s method for the point load estimation.Problem 12.10A concrete pile 15.24 m long having a cross section of 406 mm
A concrete pile 15.24 m long having a cross section of 406 mm × 406 mm is fully embedded in a saturated clay layer for which gsat = 19.02 kN/m3, ϕ = 0, and cu = 76.7 kN/m2. Determine the allowable
Determine the maximum load that can be allowed on the 450 mm diameter pile shown in Figure P12.9, with a factor of safety of 3. Use the a method and Table 12.11 for determining the skin friction and
A 400 mm × 400 mm square precast concrete pile of 15 m length is driven into a sand where γ = 18.0 kN/m3 and ϕ' = 33°. Assuming δ' = 0.7ϕ' and K = 1.4 Ko, determine the load-carrying capacity
Redo Problem 12.3 using Coyle and Castello’s methods for estimating both Qp and Qs.Problem 12.3A 500 mm diameter and 20 m long concrete pile is driven into a sand where γ = 18.5 kN/m3 and ϕ' =
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.a. Determine the maximum allowable load (Qall) with FS = 3. Use the a method and Table
Determine the maximum load that can be allowed on a 450 mm diameter driven pile shown in Figure P12.6, allowing a factor of safety of 3. Use K = 1.5 Ko and δ' = 0.65ϕ' in computing the shaft load.
A 500 mm diameter and 20 m long concrete pile is driven into a sand where γ = 18.5 kN/m3 and ϕ' = 32°. Assuming δ' = 0.7ϕ' and K = 1.5 Ko, determine the loadcarrying capacity of the pile, with a
Repeat Problem 11.1 based on LRFD using the following factors:load factor for dead load = 1.25load factor for live load = 1.75strength reduction factor on the ultimate bearing capacity = 0.50Problem
For a 2.0 m wide and 0.40 m thick beam on elastic foundation, determine the coefficient of subgrade reaction k using Eqs. (10.45) and (10.46), assuming the following parameters: Es = 30 MN/m2, EF =
A 300 mm × 450 mm plate was used in carrying out a plate loading test in a sand, where the plate settled 5 mm under the applied pressure of 250 kN/m2.a. What is the coefficient of subgrade reaction
A 1500 kN load was applied on two 20 m long and 500 mm diameter piles that were instrumented for measuring the load variation with depth.a. The variation of frictional resistance per unit area, f(z),
Repeat Problem 11.1 based on limit state design, using the factors given in Table 11.4.Table 11.4.Problem 11.1A continuous foundation is required in a soil where c' = 10 kN/m2, ϕ' = 26°, and γ =
A continuous foundation is required in a soil where c' = 10 kN/m2, ϕ' = 26°, and γ = 19.0 kN/m3. The depth of the footing will be 1.0 m. The dead load and the live load are 600 kN/m and 400 kN/m,
A plate loading test was carried out on a medium dense sand, using a 300 mm wide square plate, and k0.3 was determined as 100 MN/m3. Determine the coefficient of subgrade reaction for a 2.5 m wide
In Problem 10.7, determine the consolidation settlement under the corner of the mat.Problem 10.7A 15 m × 20 m mat foundation shown in Figure P10.7 carries a building load of 36 MN and is placed at
A 2 m wide square foundation is placed at a depth of 1.5 m, in a very thick homogeneous sand deposit where qc = 10 MN/m2 and λ = 18.5 kN/m3. The stress level at the foundation is 140 kN/m2. Estimate
Refer to Figure 9.23. For a foundation on a layer of sand, given: B = 1.52 m, L = 3.05 m, d = 1.52 m, β = 26.6°, e = 0.152 m, and δ = 10°. The pressuremeter testing at the site produced a mean
A 15 m × 20 m mat foundation shown in Figure P10.7 carries a building load of 36 MN and is placed at 3.0 m depth below the ground level.a. Find the net applied pressure on the underlying ground. The
A dilatometer test was conducted in a sand deposit at a depth of 6 m. The groundwater table was located at a depth of 2 m below the ground surface. Given, for the sand: γd = 14.5 kN/m3 and
It is proposed to build a 8 story building with a footprint of 15 m × 20 m, resting on a mat foundation of the same dimensions, in a saturated clay where cu = 50 kN/m2, γ = 19.0 kN/m3. Assume
A 12 m × 9 m mat foundation is placed at a depth of 3 m within sand where N60 is 20. Using Eq. (10.14), estimate the elastic settlement when the net applied pressure is 250 kN/m2.Eqs. (10.14) Se
A 10 m × 6 m mat foundation is placed at 2.0 m depth in sand where the average value of N60 is 23. Determine the allowable net pressure that would limit the settlement to 75 mm, using Eqs. (9.47)
A 10 m × 8 m mat foundation is to be placed at 3 m depth in a saturated clay where cu = 60 kN/m2 and ϕ = 0. Determine the net ultimate bearing capacity.
Refer to the trapezoidal combined footing in Figure 10.2, with Q1 = 1000 kN and Q2 = 500 kN. The distance between the columns L3 is 4 m, and the net allowable soil pressure is 125 kN/m2. It is
Refer to the rectangular combined footing in Figure 10.1, with Q1 = 500 kN and Q2 = 750 kN. The distance between the two column loads, L3 = 4.5 m. The proximity of the property line at the left edge
A 3.0 m wide square foundation is placed at 1.5 m depth in sand where γ = 18.5 kN/m3. The water table lies well below the foundation level. Under the applied pressure of 200 kN/m2 at the foundation
A 2 m × 2 m foundation carrying a 1000 kN column load is placed at 1.0 m below the ground level in a sand where γ = 19 kN/m3 and (N1)60 = 25. Estimate the settlement using the Berardi and
A 2 m wide continuous foundation carrying a 260 kN/m wall load is placed at a depth of 1.0 m in sand where the unit weight is 19.0 kN/m3 and (N1)60 is 32. Assuming Poisson’s ratio of 0.15, estimate
A shallow foundation measuring 1 m × 2 m in plan is to be constructed over a normally consolidated sand layer. Given: Df = 1 m, N60 increases with depth, N60 (in the depth of stress influence) = 12,
It is proposed to place a 3 m × 3 m foundation at 2 m depth in a sandy soil, where the average N60 is 25 and the unit weight is 18 kN/m3. Using Meyerhof’s expressions presented in Section 9.6,
Find the settlement of a 2.0 m wide square foundation (Df = 1.0 m) applying a net pressure of 150 kN/m2 to the underlying sand, where N60 = 20 and λ = 18.5 kN/m3.Use Eq. (9.43). In the last term of
Solve Problem 9.10 using Eqs. (9.39), (9.40), and (9.41).Problem 9.10A continuous foundation on a deposit of sand layer is shown in Figure P9.10 along with the variation of the cone penetration
A continuous foundation on a deposit of sand layer is shown in Figure P9.10 along with the variation of the cone penetration resistance qc. Assuming λ = 18 kN/m3 and creep is at the end of ten years
A plan calls for a square foundation measuring 3 m × 3 m supported by a layer of sand (see Figure 9.7). Let Df = 1.5 m, t = 0.25 m, Eo = 16,000 kN/m2, k = 400 kN/m2/m, ms = 0.3, H = 20 m, Ef = 15 ×
Refer to Figure 9.7. Estimate the elastic settlement of the foundation in sand for the following data using the method of Mayne and Poulos [Eq. (9.27)].Foundation: length L = 3 m, width B = 2 m,
A 2.0 m × 4.0 m flexible loaded area shown in Figure P9.6 applies a uniform pressure of 150 kN/m2 to the underlying silty sand. Estimate the elastic settlement below the center of the
Redo Problem 9.4 with Df = 1.0 m.Problem 9.4A 2 m × 4 m flexible foundation is placed on a granular soil with Df 5 0. The foundation applies a pressure qo = 120 kN/m2. Assuming the soil mass to be
Redo Problem 9.3 for the situation where the same soil is underlain by bedrock at 3.0 m below the surface.Problem 9.3A 2 m × 4 m flexible foundation is placed on a granular soil with Df 5 0. The
A 2 m × 4 m flexible foundation is placed on a granular soil with Df 5 0. The foundation applies a pressure qo = 120 kN/m2. Assuming the soil mass to be infinitely thick, with Es = 15 MN/m2 and
For an elastic material, the bulk modulus (K) and Young’s modulus (E) are related byFor undrained loading, deduce that µs = 0.5. 1 K = 3(1 - 2р.,)
Refer to Figure 9.1, where a 2.0 m × 3.0 m flexible foundation is placed in a saturated clay at 1.5 m depth. Bedrock lies at 4.0 m below the foundation. The clay is overconsolidated with OCR = 2,
A 2-m diameter flexible foundation applies a uniform pressure to the underlying soil of 200 kN/m2. Plot the variation of the vertical stress increase below the center of the foundation as determined
A point load of 500 kN is applied on an elastic medium with Poisson’s ratio of 0.2. Compare the vertical stress increase at the following locations as determined by the Boussinesq (ΔσB) and
Figure P.8.12 shows an embankment load on a silty clay soil layer. Determine the stress increase at points A, B, and C, which are located at a depth of 5 m below the ground surface.Figure P.8.12 K 6
A square foundation, 1.5 m wide, carries a net column load of 500 kN as shown in Figure P8.11. Determine the average stress increase beneath the center of the foundation in the clay layer:a. Using
A square flexible foundation of width B applies a uniform pressure qo to the underlying ground. Determine the vertical stress increase at a depth of B/2 below the center using:a. Δσ beneath the
A flexible L-shaped raft shown in Figure P8.9 applies a uniform pressure of 60 kN/m2 to the underlying ground. Find the vertical stress increase at 4 m below A, B, and C.Figure P8.9 - 6 m – - 8 m 4
Figure P8.8 shows a flexible rectangular raft that is 8 m × 16 m and applies a uniform pressure of 80 kN/m2 to the underlying ground. Find the vertical stress increase Δσ at 4 m below A, B, C, and
A 3 m wide and infinitely long flexible strip load of 40 kN/m2 is placed on an elastic medium as shown in Figure P8.7. Find the vertical stress increase at points A, B, and C located 1 m below the
Two line loads q1 and q2 of infinite lengths are acting on top of an elastic medium, as shown in Figure P8.6. Find the vertical stress increase at A.Figure P8.6. 30 kN/m 92 = 40 kN/m %3D 6 m + 3 m 3
For the flexible loaded area in Problem 8.4, plot the vertical stress variation with the radial distance at 0.75 m below the ground level.Problem 8.4A 3 m diameter flexible loaded area is subjected
A 3 m diameter flexible loaded area is subjected to a uniform pressure of 60 kN/m2.a. Plot the variation of the vertical stress increase beneath the center with depth z = 0 to 6 m.b. In the same
A point load of 1000 kN is applied at the ground level. Plot the variation of the vertical stress increase Δσ with depth at horizontal distance of 1 m, 2 m, and 4 m from the load.
A point load of 500 kN is applied at the ground level. Plot the lateral variation of the vertical stress increase Δσ at depths of 2 m, 3 m, and 4 m below the ground level.
Four point loads with the same magnitude of P are applied as shown in the plan view in Figure P8.1 and are separated by distance b.a. Find the vertical stress increase Δσ at a depth of 0.5b below
A foundation measuring 1.2 m × 2.4 m in plan is constructed in a saturated clay. Given: depth of embedment of the foundation = 2 m, unit weight of soil = 18 kN/m3, and undrained cohesion of clay =
A square foundation in a sand deposit measures 1.22 m × 1.22 m in plan. Given: Df = 1.52 m, soil friction angle = 35°, and unit weight of soil = 17.6 kN/m3. Estimate the ultimate uplift capacity of
A sandstone bed with RQD = 70% and γ = 26.0 kN/m3 lies beneath 1.5 m of overburden soil. A 2.0 m × 2.0 m square foundation is to be placed on top of the sandstone rock (i.e., at a 1.5 depth below
A sandstone rock specimen has quc = 50 MN/m2 and ϕ' = 35°. Find c'.
Refer to Problem 7.15. If the design earthquake parameters are V = 0.35 m/s and A = 0.3, determine the seismic settlement of the foundation. Assume FS = 4 for obtaining static allowable bearing
The following are the average values of cone penetration resistance in a granular soil deposit.Depth (m) …………………… Cone penetration resistance, qc (MN/m2)2
A continuous foundation is to be constructed near a slope made of granular soil (see Figure 7.19). If B = 1.22 m, b = 1.83 m, H = 4.57 m, Df = 1.22 m, β = 30°, ϕ' = 40°, and γ = 17.29 kN/m3,
The applied load on a shallow square foundation makes an angle of 208 with the vertical. Given: B = 1.52 m, Df = 0.9 m, γ = 18.08 kN/m3, ϕ' = 258, and c' = 28.75 kN/m2. Use FS = 4 and determine the
Redo Problem 6.2 using the general bearing capacity equation [Eq.(6.28)].Eq. (6.28)Problem 6.2A 1.5 m wide square footing is placed at 1 m depth within the ground where c' = 10 kN/m2, ϕ' = 258, and
A 1.5 m wide square footing is placed at 1 m depth within the ground where c' = 10 kN/m2, ϕ' = 258, and γ = 18 kN/m3. Determine the ultimate bearing capacity of the footing using Terzaghi’s
For a cohesive soil with LL = 45 and PL = 25, estimate the difference in the wopt and γd(max) values between standard and modified compaction tests. Use Gurtug and Sridharan (2004) correlations.
A continuous foundation with a width of 1 m is located on a slope made of clay soil. Refer to Figure 7.19 and let Df = 1 m, H = 4 m, b = 2 m, γ = 16.8 kN/m3, c = cu = 68 kN/m2, ϕ = 0, and b =
Two continuous foundations are constructed alongside each other in a granular soil. Given for the foundation: B = 1.2 m, Df = 1 m, and center-to-center spacing = 2 m. The soil friction angle ϕ' =
A 2 m wide continuous foundation is to be placed in a saturated clay at 1.5 m depth where cu = 40 kN/m2 and γ = 18.0 kN/m3.a. What is the ultimate bearing capacity of the foundation?b. To increase
A continuous foundation having a width of 1.5 m is placed at 1.0 m depth within a loose sand deposit where ϕ' = 32° and γ = 17.0 kN/m3. This sand is underlain by a thick dense sand deposit (ϕ' =
A 3 m thick clay layer (cu = 60 kN/m2 and γ = 19.0 kN/m3) is underlain by a weaker clay (cu = 30 kN/m2 and γ = 18.0 kN/m3) to a large depth. A 2.0 m wide square foundation is placed at 1.5 m depth
A 2 m wide continuous foundation is placed at 1 m depth within a 1.5 m thick sand layer that is underlain by a weaker clay layer. The soil properties are as follows:Upper sand layer: unit weight =
Redo Problem 7.6 using Vesic’s (1975) solution [Eq. (7.12)].Eq. (7.12)Problem 7.6A 2.0 m wide continuous foundation is placed at 1.5 m depth in a saturated clay where cu = 40 kN/m2 and γ = 18.5
A 2.0 m wide continuous foundation is placed at 1.5 m depth in a saturated clay where cu = 40 kN/m2 and γ = 18.5 kN/m3. At 2.0 m below the ground level, this clay layer is underlain by a stiffer
A 2.0 m wide square foundation is placed at 0.5 m depth in a saturated clay where cu = 40 kN/m2 and γ = 19.0 kN/m3. There is a very stiff stratum present at 1.0 m below the foundation.
In Problem 7.3, if no bedrock was present for at least 4 m below the foundation, determine the ultimate bearing capacity.Problem 7.3A 1.5 m × 2.0 m rectangular foundation is placed at 1.0 m depth in
A 1.5 m × 2.0 m rectangular foundation is placed at 1.0 m depth in sand where ϕ' = 40° and γ = 18.5 kN/m3. Bedrock is present at 1.0 m below the foundation. Using Eq. (7.3), determine the
In Problem 7.1, if there was no bedrock present for at least 4 m below the foundation, what would the ultimate bearing capacity be?Problem 7.1A 2.5 m wide rough continuous foundation is placed in the
A 2.5 m wide rough continuous foundation is placed in the ground at 1 m depth. There is bedrock present at 1 m depth below the bottom of the foundation. The soil properties are c' = 10.0 kN/m2, ϕ' =
Consider a continuous foundation of width B = 1.4 m on a sand deposit with c' = 0, ϕ' = 38°, and γ = 17.5 kN/m3. The foundation is subjected to an eccentrically inclined load (see Figure 6.33).
The shallow foundation shown in Figure 6.25 measures 1.5 m × 2.25 m and is subjected to a centric load and a moment. If eB = 0.12 m, eL = 0.36 m, and the depth of the foundation is 0.8 m, determine
A square foundation is shown in Figure P6.19. Use FS = 6, and determine the size of the foundation. Use Prakash and Saran's method [Eq. (6.59)].Figure P6.19. 450 kN 70 kN-m y = 16 kN/m3 c' = 0 o'=
An eccentrically loaded continuous foundation is shown in Figure P6.18. Determine the ultimate load Qu per unit length that the foundation can carry. Use the reduction factor method [Eq.
A 2.0 m × 2.0 m square pad footing will be placed in a normally consolidated clay soil to carry a column load Q. The depth of the footing is 1.0 m. The soil parameters are: c' = 0, ϕ' = 26°, γ =
A tall cylindrical silo carrying flour is to be supported by a 1.5 m wide ring beam that can be designed as a continuous foundation. The inner and outer diameters of the ring are 10 m and 13 m,
Three continuous foundations are shown in Figure P6.15. For each of them, what values would you use for their eccentricity and inclination in the bearing capacity calculations?Figure P6.15. |500 kN/m
A 2 m × 3 m spread footing placed at a depth of 2 m carries a vertical load of 3000 kN and a moment of 300 kN ∙ m, as shown in Figure P6.14. Determine the factor of safety using Meyerhof’s
For an eccentrically loaded continuous foundation on sand, given B = 1.8 m, Df = 0.9 m, e/B = 0.12 (one-way eccentricity), γ = 16 kN/m3, and ϕ' = 35°. Using the reduction factor method [Eq.
Repeat Problem 6.11 using Prakash and Saran’s method.Problem 6.11An eccentrically loaded foundation is shown in Figure P6.11. Use FS of 4 and determine the maximum allowable load that the
An eccentrically loaded foundation is shown in Figure P6.11. Use FS of 4 and determine the maximum allowable load that the foundation can carry. Use Meyerhof’s effective area method.Figure P6.11.
For the design of a shallow foundation, given the following:Soil: ϕ' = 20°c' = 72 kN/m2Unit weight, γ = 17 kN/m3Modulus of elasticity, Es = 1400 kN/m2Poisson’s ratio, µs = 0.35Foundation: L = 2

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