Empirical equations for predicting pile/soil setup effect

Pile/soil setup effect is a natural phenomenon where pile load capacity increases over time as the results of dissipation of pore-water pressure and soil aging. The magnitude of pile/soil setup is governed by three main factors, i.e. pile slenderness ratio, elapsed time and type of surrounding soil. In this study, empirical correlations were established based on data compiled from previous case studies. Two forms of empirical equations were proposed to predict the pile/soil setup effect subjected to different slenderness ratios and elapsed times. The proposed equations were subsequently verified by actual field data collected from two sites in Malaysia. Results showed that 80% of the pile capacities increased by 1.150-1.875 times per log time cycle. Piles in fine-grained soils generally exhibited a greater pile/soil setup effect than coarse-grained soils.