Foundation design using penetration resistance data

4 FOUNDATION DESIGN USING PENETRATION RESISTANCE DATA 

Empirically developed foundation design methods are typically based on the averaged or representative performance of case studies, but they will be conservative. Practically, deviations will always exist between individual cases and the design recommendations. 

empirical design methods are recommended only for preliminary studies. Realistically, designers frequently need also to apply the procedures to final designs because of lack of further information. 

Subsequent studies, which included performance evaluations of foundations designed in accord with the original recommendations, have indicated that modification of the original design criteria is necessary where greater allowable bearing pressures can be permitted. When SPT values are used for foundation design, the field blow counts need to be corrected to reflect the effect of sample depth on actual soil properties. 

In recent times, investigations utilizing penetrometer methods have received considerable attention in virtually all areas of the world. Interest has been generated by developing awareness that direct relationships between penetrometer results and foundation design have been formulated. 

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