The Unit Weight of Soil

  1. A wall footing 3 ft. wide is located 5.0 ft. below the ground surface. The supporting soil has a unit weight of 120 pcf. The results of the laboratory tests on the soil samples indicate that the cohesion and the angle of internal friction of the supporting soil are 1200 psf and 2• respectively. Groundwater was not encountered during the sub-surface soil exploration. Determine the allowable bearing capacity, using a factor of safety of 3.
  2. A shallow square foundation is subjected to a vertical load and a moment. Given: Vertical load = 100,000.001b, Moment = 50,000.00 lb.ft. D = 4 ft, water table is at a depth of 4.0 ft from the ground surface, soil properties are y (saturated) = 120, and dry 110 pcf, c = 0 and 4:0= 30% Determine the size of the footing, using a factor of safety of 3. 3. For the footing shown in figure 1, the vertical load, including column load, surcharge weight, and the weight of footing, is 100 kips. A horizontal load of 8 kips and a moment of 60 ft. kips are also imposed on the foundation. a) Compute the soil contact pressure and draw the soil contact pressure diagram. b) Compute the shear and moment on Section a-a.
    e kihr
    5\ 4- t
    /046 kips’ ct. leipc
    I a
    k k I 2 v2v-
    a-1/ 4 +

Sample Solution