Drilled Pier Lateral Analysis Theory

STAAD Foundation Advanced performs lateral analysis of drilled pier based on a nonlinear pile and p-y Model for soil (more conceptual information is available from UFC 3-220-01A [PDF]).

Nonlinear Pile

STAAD Foundation Advanced calculates nonlinear bending stiffness of pile.

Example plot of nonlinear bending stiffness of pile

P-Y Curve Method

The p-y curve method was suggested in 1958 by McCelland and Focht. It is a very practical approach to deal with complex lateral resistance behavior of different soils. Field tests using strain gauges were carried out for different soil and based on experimental data correlation between soil parameters and lateral response is derived.

Typical P-Y curve for clay soil type using Unified Clay Method for both cyclic and static loading

Conceptual spring representation of soil resistance at various depths

A solution is derived by converging pile and soil nonlinearity.