A Plate load test is a field test which is used to determine the bearing capacity and settlement of soil.
The calculation of bearing capacity is perfomed using the following steps.
- Plotting the load settlement curve
- Assessing the failure point on load settlement curve
- Calculation of safe bearing capacity
- Determining settlement of proposed footing
Calculation of the ultimate resistance of soil (R) using the formula
R = Ultimate resistance of soil in kg
d = Average depth of impression in cm
w = Weight of soil ball in kg
h = Height of fail of soil ball in cm
A = cross sectional area
Therefore the resistance of soil is R/A in kg/cm squared
Safe bearing capacity is R/(A * FOS)
FOS is the Factor of Safety
The FOS will be between 2 to 3 depending on the type of structure and the site conditions.