WHAT IS PRESUMPTIVE BEARING CAPACITY OF SOIL AND ITS VALUES?

What is the presumed bearing capacity?

The building codes of different organizations in different countries gives acceptable bearing capacity which can be used on a proportionate basis. These are called presumptive bearing capacity values. These values ​​are based on the experience of other structures already built.


What are the values ​​of presumptive bearing capacity?

The table below shows the estimated bearing capacity values ​​for different soil types.


soil/rock type

Safe / Acceptable Bearing Capacity (KN/m)2,

Rock

3240

soft stone

440

coarse sand

440

medium sand

245

fine sand

440

soft shell / hard clay

100

soft clay

100

very soft clay

50

notes

  1. Values ​​for non-adhesive soils should be reduced by 50% if the water level is above or near the base.
  2. These values ​​should only be used for the initial design. The actual bearing capacity of the soil should be calculated as per the standard code.

What are the limitations of using presumptive bearing capacity values?

  • Estimated bearing capacity values ​​are based on visual classification of surface soils only. So these values ​​are not a true representation of the actual potential and are not reliable.
  • These values ​​do not consider the important factors affecting bearing capacity; Such as size, width, depth of the bed, location of water table, soil strength and compressibility.
  • These values ​​are conservative and can be used only for the initial design or even for the final design of small insignificant structures.

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.