Concept explainers
A continuous foundation is required in a soil where
Find the required width for the foundation.
Answer to Problem 11.1P
The required width for the foundation is
Explanation of Solution
Given information:
The unit weight
The cohesion
The soil friction angle
The depth
The dead load is 600 kN/m.
The live load is 400 kN/m.
The factor of safety is 3.
Calculation:
Refer Table 6.1, “Terzaghi’s bearing capacity factors” in the text book.
For
Take the value of
Take the value of
Take the value of
Determine the ultimate bearing capacity of the foundation
Determine the allowable bearing capacity of the foundation
Find the design load.
Find the required width for the foundation:
Hence, the required width for the foundation is
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Chapter 11 Solutions
MindTap Engineering, 1 term (6 months) Printed Access Card for Das/Sivakugan’s Principles of Foundation Engineering, 9th
- Consider a continuous foundation of width B = 1.4 m on a sand deposit with c = 0, = 38, and = 17.5 kN/m3. The foundation is subjected to an eccentrically inclined load (see Figure 6.33). Given: load eccentricity e = 0.15 m, Df = 1 m, and load inclination = 18. Estimate the failure load Qu(ei) per unit length of the foundation a. for a partially compensated type of loading [Eq. (6.89)] b. for a reinforced type of loading [Eq. (6.90)]arrow_forwardA 2.0 m wide continuous foundation carries a wall load of 350 kN/m in a clayey soil where = 19.0 kN/m3, c = 5.0 kN/m2, and = 23. The foundation depth is 1.5 m. Determine the factor of safety of this foundation using Eq. (6.28).arrow_forwardA strip footing is to be designed to support a dead load of 500 kN/m and an imposed load of 300 kN/m at a depth of 0.7 m in a gravelly sand. Characteristic values of the shear strength parameters are c' = 0 and ϕ' =40˚. (a) Determine the required width of the footing if a factor of safety of 3.0 and assuming that the water table may rise to foundation level. (b) Would a foundation of that width satisfy the bearing resistance limit state? The unit weight of the sand above the water table is 17 kN/m3 and below the water table the saturated unit weight is 20 kN/m3.arrow_forward
- A square foundation is placed at a depth of 1.5 m within a sandy clay where c'=14k/m2 , phi'=23 and y=18 kN/m3 to carry a column load of 950 kN. Determine the width of the foundation that can be allowed on the foundation with a factor of safety of 3 and use the width value you have found to calculate the allowable bearing capacity(assume general shear failure and use gross values for the Terzaghi Bearing Capacity formulation for the given foundation type). If you don't write down the required equation to find the width of the foundation you cannot get credit from this question. Use the table given to you in the figure.arrow_forwardA column foundation is 3 m × 2 m in plan. Given: Dƒ = 1.5 m, þ' = 30°, c′ = 80 kN/m². Using the general bearing capacity equation (CFEM see class slides from March 17 similar to Example 1 and 2 but with an added capacity term related to cohesion) and 0.5, determine the factored bearing capacity of the foundation (i.e. – use Þ). Use Yw = 9.81 kN/m³. For simplicity, read the values of Nc, Ną, and Ny directly from the table on page 26 of the lecture slides use the highlighted columns. Also, determine the maximum factored load for the column. - 1.5 m ↑ 1 m 3m x 2m - y = 17 kN/m³ Groundwater level Ysat = 19.5 kN/m³ =arrow_forward(a) Design a Shallow Foundation to support a dead load of 500 kN/m and an imposed load of 300 kN/m in a silty sand. Characteristic values of shear strength parameters are c|= 10 kN/m2 and ø| = 40°. The saturated unit weight of the soil is 20 kN/m3 and the unit weight above the water table is 17 kN/m3 . (a) determine the required size, shape and depth of the footing if a lumped factor of safety of 3.0 against shear failure is specified and assuming that the water table (i) is well below the foundation level (ii) may rise to foundation level (iii) may rise to the surface (b) determine if a foundation of that size, shape and depth would satisfy the bearing resistance limit state?arrow_forward
- A square shallow foundation (B × B) is planned to be constructed on a normality consolidated (NC) clay soil as shown in the below figure. The maximum acceptable settlement for the foundation is equal to 2.0 inches (5 cm), and the safety factor against bearing capacity is FS = 4. Determine the size of foundation. (Note: To simplify the calculations, ignore both the elastic settlement and secondary compression settlement. Also consider 4o'ave = 40'm) Q = 500 kN Ysat = 19.24 kN/m³ en = 0.8 C. = 0.25 p'= 0 c'= 25 kPa 2 m B ×B FS again Bearing Capacity = 4 Acceptable settlement = 2.0 inches 10 marrow_forwardA square shallow foundation (B × B) is planned to be constructed on a normality consolidated (NC) clay soil as shown in the below figure. The maximum acceptable settlement for the foundation is equal to 2.0 inches (5 cm), and the safety factor against bearing capacity is FS = 4. Determine the size of foundation. (Note: To simplify the calculations, ignore both the elastic settlement and secondary compression settlement. Also consider Ao'ave = 4o'm) Q = 500 kN Ysat = 19.24 kN/m³ eo = 0.8 C. = 0.25 p'= 0 c' = 25 kPa FS again Bearing Capacity = 4 Acceptable settlement = 2.0 inches 2 m В ХВ 10 marrow_forwardA footing 2.50 m x 2.50 m is located at a depth of 1.5 m in sand. The shear strength parameters to be used in design are c' = 0 and o' = 38°. What is the net ultimate bearing capacity of footing if the water table is at 3 m below foundation level? The unit weight of sand is 18 kN/m3 and FOS = 3 For O' = 38°, N, = 67 and Ng = 49arrow_forward
- 4. A square footing shown has a dimension of 1 x 1 m. has its bottom 2.5 m. below the ground surface. Angle of friction of the soil foundation is 30°. Unit weight of soil is 18.1 kN/m³ with a cohesion of 15.7 kN/m². Saturated unit weight of soil is 19.3 kN/m³ and F.S. is 3.0 a. Compute the value of the bearing capacity factor Nq. b. Compute the net allowable load that the footing could carry if the ground water table is located 0.20 m. below the foundation footing. c. Compute the net allowable load that the footing could carry if the ground water table is located 1.2 m below the ground surface. 25m B=1.0 m Ground surface C=157 KP -30 Y 18.1 kN/m Year 19.3 kN/marrow_forwardA square footing is proposed to be constructed on the silty sand layer as shown in Figure Q2. If the gross load (Qall) is 600 kN, check whether the foundation can carry the load or not. (Use Terzaghi's bearing capacity equation with general shear failure and FS = 3). 2. Qall Silty Sand 1.5 m y 19 kN/m c' 8 kN/m2 = 25° Ground Water 0.5 m 1.2 m Level Kar 19.0 kN/m' Figure Q2: A Square Footingarrow_forwardIt is planned to construct a rectangular foundation with base dimensions of 8 * 14 m (B* L) on the construction site with the ground profile as in the figure. Accordingly, if the YASS descends 9 m, what would be the change in the final bearing capacity of the ground? Note: Make your calculation using the Terzaghi bearing capacity formula as the safety factor of 3 0m c=18 kPa, -18° Y=20 kN/m³ Y-21,8 kN/m³ 1.5 m SM H e=0.67 2.7 m GW 12 m c=8 kPa, -23° e=0.23 Yo=22 kN/m³ Y-23,2 kN/m³arrow_forward
- Principles of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781337705028Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage Learning