Final Exam - Geotechnical Engineering II

Terzhagi’s bearing capacity estimation is based on these assumptions:

i. Depth is higher than the width of footing

ii. General shear failure governs

iii.Soil is heterogeneous mass

iv.No Sliding between footing and soi

• a.) all of the above

• b.) i & iii

• c.)i, ii, & iv

• d.) ii & iv

2.) Bearing capacity failures are caused by these:

i. Excessive Settlement

ii. Regulated structural loads

iii.Shear strength mobilization

iv.Rising of Ground water level

• a.) i, iii, & iv

• b). i, ii & iii

• c.) i, & iii

• d.) i & iv

3.) Bearing capacity depends on

i. Location of ground water table

ii. Type of structure and weight

iii. Settlement and strength limits

iv. Economy of construction

v. Mode of shear failure

• a.) i, ii, iii & iv

• b.) i, ii, iii & v

• c.) i, iii, iv & v

• d.) all of the above

4.) Shallow foundations in general have a depth-of-embedment to-width ratio of approximately

• a.) 4

• b.) 2

• c.) 4 or more

• d.) 1

5-8. Given: Ɣ = 19.5 kN/m³, Ɣsat = 20.5 kN/m³ ,cu = 37 kN/m², Ǿ = 0, Df = 0.75 m, B = 2.5 m, and factor of safety 6. Using Terzaghi’s bearing-capacity factor,

5.) Determine the gross allowable load per unit area (qall) that the continuous footing can carry considering excavation not backfilled. Neglect ground water.

• a. 85 KPa

• b. 50 KPa

• c.30 KPa

• d. 40 KPa

5-8. Given: Ɣ = 19.5 kN/m³, Ɣsat = 20.5 kN/m³ ,cu = 37 kN/m², Ǿ = 0, Df = 0.75 m, B = 2.5 m, and factor of safety 3. Using Terzaghi’s bearing-capacity factors,

6.) If ground water table rises to the ground surface how much reduction of the bearing capacity?

• a. 10%

• b. 20%

• c.15%

• d. 8%

5-8. Given: Ɣ = 19.5 kN/m³, Ɣsat = 20.5 kN/m³ ,cu = 37 kN/m², Ǿ = 0, Df = 0.75 m, B = 2.5 m, and factor of safety 3. Using Meyerhof bearing-capacity equation,

7.) what is the gross qall of the strip footing without backfilled in number 5 assuming L=5B? Neglect ground water.

• a. 92 KPa

• b. 80 KPa

• c.78 KPa

• d. 101 KPa

5-8. Given: Ɣ = 19.5 kN/m³, Ɣsat = 20.5 kN/m³ ,cu = 37 kN/m², Ǿ = 0, Df = 0.75 m, B = 2.5 m, and factor of safety 3. Using Terzaghi’s bearing-capacity equation,

8.) If a load of 150 KN is allowed to deviate from the center about 0.30 m along width B, is there a change in the bearing pressure in the footing in this case?

• a. no increase

• b. there is increase

• c. not affected

• d. none of the above

9. A square footing (B x B) must carry a gross allowable load of 1111 kN. The base of the footing is to be located at a depth of 1.37 m below the ground surface. Use Terzaghi’s bearing-capacity factors and assume general shear failure of soil. Given: Ɣ = 18.2 kN/m³, c = 43 kN/m², Ǿ = 29°.

9.) If the required factor of safety is 3, What is the size of the footing in m?

• a. 3

• b. 2

• c.4

• d.5

10.) What is the importance of Factor of safety?

i. Considers the level of uncertainty of strength parameters

ii. Soil is uniform and predictable so FS could be estimated directly

iii. Each type of structure has degree of failure so FS may vary

iv. Load occurrence is taken into account in FS

• a. i, ii, iii

• b. i & ii

• c. i, iii, iv

• d. . ii, iii, iv