A Review of Load Transfer Concept of Single Piles Considering Soil Nonlinearity

Pile response to a vertical load can conveniently be studied using load-deformation behaviour of piles. The load-deformation behaviour of pile can be determined either by conducting an expensive field test or predict numerically using the in situ soil parameters. Several approaches have been proposed to predict the load-deformation behaviour numerically. Two such approaches often used are finite element (FE) analysis and load transfer method. FE analysis is expensive and requires a very skilled person to execute the analysis. The load transfer method is much simpler, easy to use for the analysis and recommended by the API. In the load transfer method, the soil structure interaction has been expressed in terms of t-z curve, the t represents shear stress at the pile shaft, and z is the relative deformation between soil and pile at the interface. This t-z curve varies with depth, soil-pile interface friction angle, and the pile installation. This paper critically reviews several t-z curves based on the theoretical, empirical, semi-empirical, elastic, and nonlinear methods that have been used in the past to study the load transfer concept of the single pile. The development, limitation, and range of applicability of these models are also explored in detail.