NONLINEAR ANALYSIS Of TORSIONALLY LOADED PILE GROUPS

An empirical approach to analyze the torsional behavior of pile groups in which single-pile response is modeled by means of load-transfer curves, including an empirical factor to model the interaction between lateral and torsional response, is studied. The centrifuge tests were carried out on piles arranged in 1×2, 2×2, and 3×3 configurations, with a centre-to-centre spacing of three pile diameters and connected by a rigid cap with a clearance of 1.2 m from the groundline in the prototype. A good agreement between test data and numerical predictions is observed for the 1×2 and 2×2 groups, while the numerical analyses tend to overpredict the pile resistance at high load levels for the 3×3 groups. When a pile group is subjected to torsion, the sustained torque by each pile in the group is shared by the pile torsional component plus the lateral contribution from the pile shear force.