Assignment # 02(Foundation Engineering)

Assignment # 02(Bearing Capacity Analysis)

Q # 01:What will be the gross & net safe bearing pressure of sand having = 36 & effective unit wt of 1.8g / cc under the following cases?1) 1.0 m wide strip footing

2) 1.0x 1.0 m square footing

3) Circular footing of 1.0 m dia

Q# 02:For sand = 360, = 1.8g / cc & strip footing having width = depth = 1m, what will be the safe net B.C under the following condition of Ground water table (G.W.T).

01) W.T touching the base of foundation

02) W.T touching the ground surface.

Assume saturated unit wt of soil = 2.13 g / cc

The soil is assumed to remain saturated below ground surface.

C = 0, F.O.S = 3,Nq = 49.38, Nr = 54

Q# 03:What will be net ultimate Bearing capacity of a soft sensitive clay, in which, when a vane shear test was conducted ( vanes of 10 cm height & 8 cm diameter), the soil failed at a maximum Torque of 500 N-cm. consider a footing of square shape & density of soil as 1.7 gm / cm3. use Terzaghis Theory. Q# 04:A square footing 2.5m x 2.5m is built in a homogenous bed of sand of density 2.0 T / m3 & having an angle of shearing = 380. The depth of the base of footing is 1.5m below the G.S. Calculate the safe load that can be carried by a footing with a F.O.S 3 against complete shear failure. Use terzaghi analysis.Q# 05:What will be the max safe load for = 1.6 T / m3, = 270footing size = 2.5 m X 2.5 m, C = 0, Df = 1.5m &soil is lose sand. Q# 06A strip footing, 1 m wide at its base is located at a depth of 0.8 m below the ground surface. The properties of the foundation soil are 1.8 ton / m3, C = 3 T / m2, = 200 .Determine the safe B.C, using a factor of safety of 3. Assume the soil fails by local shear. Q# 07: A strip footing, 1m wide at its base, at a depth of 0.8m, = 1.8 T / m3 , C = 3 T / m2, = 200 , If W/T is 1.5m below the ground surface, find out bearing capacity of soil.

Q# 08: A strip footing of width = 3m is founded at a depth of 2m below ground surface in a (C- ) soil having = 18 KN / m3, C = 30 KPa, = 360. Determine the ultimate bearing capacity of soil by the method of Rankine.

Q # 09: A square footing of size 3x3m rests at a depth of 2m in medium dense sand. The W/T is at the base level of the footing. The corrected average SPT value is 30 for the soil below the base for a depth equal to the width of foundation. Compute the net ultimate bearing capacity of the soil by Tengs Method.Q# 10: At what depth should a raft of size 6x9m be founded to provide a factor of safety 3, if the soil is stiff clay having an unconfined compressive strength of 120 KN/m3? The unit weight of the soil is 18 KN/m3. The pressure transferred by the raft to its base is 150 KN/m2.Ni Factors for use in Terzaghis bearing capacity equations

(degree)NcNqN

05.71.00.0

56.81.60.05

109.62.80.65

1512.54.51.8

2017.57.45.0

2522.512.711.1

3037.221.819.6

3557.641.542.5

4096.881.5109.5

45172.9173.3271.8

50266.9319.1262.9

Shape Factors used in Tewrzaghis EquationsShape FactorStripCircularSquareRectangular

Sc11.31.3(1+0.2B/L)

S10.60.8(1-0.2B/L)

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