An Update on Pile-CPTu Direct Correlations

The axial pile capacity can be estimated from the cone penetration test (CPT) using either /Iindirect methods/N or /Idirect methods/N. The indirect methods employ a dual-phase methodology of estimating the geoparameters for evaluating the shaft and base resistance (f/Dp/N and q/Db/N, respectively) of the pile capacity. The direct methods use the penetrometer readings to directly obtain f/Dp/N and q/Db/N. These correlation efforts from the results of pile and penetrometer testing have resulted in a large variety of design methodologies. The newer multi-channel piezocone test (CPTu) device allows for derivation of more elaborate correlations. To update the pile design formulations, a quick review of the CPTu-based methods is presented, followed by the results of a comprehensive study, where the most updated and the largest pile-CPTu database were used. Simplified correlations, based on cone soil classification index (I/Dc/N), are presented for f/Dp/N and q/Db/N for different pile types.