Design of Laterally Loaded Drilled Piers

This paper presents the results of an applied research study directed at improving the state-of-practice, and resulting foundation economy, in the design of laterally loaded drilled pier foundations subjected to high ground-line moments or high ground-line shears. A theoretical four-spring, subgrade modulus model was developed in this study and was subsequently modified using the results of 14 full-scale load tests. The resultant semi-empirical nonlinear model formed the basis for the development of a design/analysis computer program (PADLL) for drilled pier foundations embedded in multi-layered subsurface profiles. The predicted behavior of two test piers, using both state-of-practice techniques and PADLL, are compared with measured behavior. Potential cost savings associated with piers designed using the semi-empirical model are discussed.