Answered Soil Bearing Capacity

Amuthakumar

Newbie
Feb 20, 2019
5
1
India
BEARING CAPACITY OF SOIL

PROCEDURE
  1. Excavate a pit of required depth. (preferably equal to the depth of foundation)
  2. Take a solid ball or square cube of known weight and dimension.
  3. Drop the ball or square cube several times, from a known height on to the bottom surface of excavated pit.
  4. Calculate the average depth of impression made several times on the bottom surface of the excavated pit. Let “d” is the average depth of impression.
CALCULATION
Calculate the ultimate resistance of soil ( R ) using the formula given below.
R = (w * h) / d
Where,
R = Ultimate resistance of soil (in kg)
d = Average depth of impression (in cm)
w = Weight of the solid ball or square cube (in kg)
h = Height of fall of solid ball or cube (in cm)
If “A” is the cross-sectional area of the solid steel ball or cube, then resistance of soil per unit area is calculated using following formula.
Resistance of soil per unit area (in kg/cm2) = R / A
Safe bearing capacity (in kg/cm2) = R / (A * F.O.S)
Where,
F.O.S = Factor of safety
NOTES TO REMEMBER
  1. F.O.S varies from 2 to 3 depending upon the type of structure and site condition.
  2. In order to get reliable test result, perform this test on different types of soil and then use your judgment to reach at any conclusion.
  3. Instead of using solid steel ball or square cube, we can also use CBR test plunger, or Cone (used for cone penetration test)
PRESUMPTIVE BEARING CAPACITY
The table given below shows the presumptive bearing capacity values for different types of soils. This table will guide you to reach at any conclusion after conducting the test.
Type of Soil / RockSafe / Allowable Bearing Capacity (kg/cm2)
Rock32.40
Soft rock4.40
Coarse sand4.40
Medium sand2.45
Fine sand4.40
Soft shell / Stiff clay1.00
Soft clay1.00
Very soft clay0.50
 
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Reddy

Senior Member
Sep 8, 2017
71
30
BEARING CAPACITY OF SOIL

PROCEDURE
  1. Excavate a pit of required depth. (preferably equal to the depth of foundation)
  2. Take a solid ball or square cube of known weight and dimension.
  3. Drop the ball or square cube several times, from a known height on to the bottom surface of excavated pit.
  4. Calculate the average depth of impression made several times on the bottom surface of the excavated pit. Let “d” is the average depth of impression.
CALCULATION
Calculate the ultimate resistance of soil ( R ) using the formula given below.
R = (w * h) / d
Where,
R = Ultimate resistance of soil (in kg)
d = Average depth of impression (in cm)
w = Weight of the solid ball or square cube (in kg)
h = Height of fall of solid ball or cube (in cm)
If “A” is the cross-sectional area of the solid steel ball or cube, then resistance of soil per unit area is calculated using following formula.
Resistance of soil per unit area (in kg/cm2) = R / A
Safe bearing capacity (in kg/cm2) = R / (A * F.O.S)
Where,
F.O.S = Factor of safety
NOTES TO REMEMBER
  1. F.O.S varies from 2 to 3 depending upon the type of structure and site condition.
  2. In order to get reliable test result, perform this test on different types of soil and then use your judgment to reach at any conclusion.
  3. Instead of using solid steel ball or square cube, we can also use CBR test plunger, or Cone (used for cone penetration test)
PRESUMPTIVE BEARING CAPACITY
The table given below shows the presumptive bearing capacity values for different types of soils. This table will guide you to reach at any conclusion after conducting the test.
Type of Soil / RockSafe / Allowable Bearing Capacity (kg/cm2)
Rock32.40
Soft rock4.40
Coarse sand4.40
Medium sand2.45
Fine sand4.40
Soft shell / Stiff clay1.00
Soft clay1.00
Very soft clay0.50
Good information keep it up
 
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