Generalized Nonlinear Softening Load-Transfer Model for Axially Loaded Piles

This paper presents the derivation of a generalized nonlinear softening load-transfer model to analyze the load-settlement response for a single pile subjected to axial loading. The model requires the calculation of a single parameter, n, so that the number of field trial tests can be reduced significantly compared with other empirical solutions with multiple parameters. Variations in n can provide approximations for different soil-pile interaction systems. The model explicitly considers both the hardening and degradation behavior of skin friction with shear displacement. The effectiveness of the proposed method was verified through comparison of the evaluations with field measurements and other analysis results. A hyperbolic load-settlement model of pile-point resistance was incorporated with the load-transfer function for skin friction to develop an efficient computer program for settlement analysis of axially loaded piles. A comparison was made between the current approach and other analyses. Satisfactory performance was obtained for the new calculation framework, where the estimated settlement differed within 13%. In this paper, the softening effect of load-settlement response of a pile is also illustrated in a worked example.