Bearing Capacity (Single Layer)

The SBC-Single Layered spreadsheet is set up to calculate Bearing pressure of single layered soil. Although this is an idealized case and is seldom a practical soil stratification, this sheet can be used to compare bearing capacity values computed by following methods:

• Mayerhof (1963)
• Terzaghi (1943)
  
• Hansen (1970)
• Vesic (1975)
• Mayerhof (1956, 1974) - Correlated from SPT
• Schmertmann (1978) - Correlated from CPT

Download here.

SBC from SPT

Here is a small User Defined Function (UDF) to quicly calculate safe bearing capacity from SPT Value. 

Download SPTSBC UDF

Formula used: Bowles Book (5th Edition) - Section 4-10

UDFs have no tooltips but there is a workaround to display tooltip-like hints while using the formula.

• First import the sbtsbc.bas (In VBA window, CTRL+M to import .bas file)
  
• Start typing the UDF: =sbtsbc(then press CTRL+SHIFT+A)  and your function parameter will be displayed

Parameters for input are:

Er - Energy efficiency of the SPT Hammer (55% or 70%)

B - Width of the footing (m)

N - Fild SPT N value (blows per 300mm)

D - Depth of footing (m)