Bearing capacity problem example 7

A rectangular footing of size 10 x 20 ft is founded at a depth of 6 ft below the ground level in a cohesive soil (0 = 0) which fails by general shear. Given: ysal =114 lb/ft3, c = 945 lb/ft2. The water table is close to the ground surface.
Determine q , q and qna by
(a) Terzaghi’s method, and
(b) Skempton’s method. Use Fv = 3.
Solution
(a) Terzaghi’s method
Terzaghi's method solution
 
(b) Skempton’s method
From Eqs. (12.22a) and (12.22d) we may write
 
Skempton's method solution
 
Note: Terzaghi’s and Skempton’s values are in close agreement for cohesive soils

  1. Rectangular footing considered to support the column loading as shown below
    a. Proportion footing
    b. Design the rectangular footing
    qall=150kpa
    Use c_25
    S_300
    Dl=500
    Ll=200