Substructure Calculations

The ground properties given in the exam tend to be stated in terms of SPT 'N'.

SPT stands for Standard Penetration Test, a simple and widely used method of ground investigation. The test is carried out by sinking a sampler inside a borehole and striking it repeatedly with a "hammer" of known weight dropped a known height. The number of blows required to progress the sampler 300mm through the strata is known as the SPT 'N' value and can be correlated with ground properties.

This cheat sheet contains a method for calculating an undrained bearing capacity in accordance with BS8004, which is non-contradictory complimentary information to BS EN 1997.

The method is similar to the one set out in Annex D of BS EN 1997-1, but includes some additional factors to account for depth, ground inclination and rigidity of the base.

This cheat sheet contains a method for calculating a drained bearing capacity in accordance with BS8004, which is non-contradictory complimentary information to BS EN 1997.

The method is similar to the one set out in Annex D of BS EN 1997-1, but includes some additional factors to account for depth, ground inclination and rigidity of the base.