The lateral response of single free headed piles in sandy soils - methods, measurements and reliability

Abstract

Piles require withstanding lateral loads from various sources such as wind, waves, traffic, earthquake, soil and water. While the Strength Limit State controls the design of axially loaded piles, serviceability often controls the design of laterally loaded piles, i.e. the applied load is controlled by the magnitude of the limiting lateral displacement. The analysis of laterally loaded piles is complicated due to the pile-soil interaction, where the lateral soil resistance developed along the pile is a function of the pile's deflection being a function of the soil's resistance. Laterally loaded piles are commonly designed using computer-based analysis methods solving the differential equation of a beam on elastic foundation that controls the load-deflection relations, utilizing what is known as p-y curves for the local spring factor-load- deflection relations. Software packages; LPile 5 Plus in which the p-y curves are constituted based on past pile load tests and soil testing results, and the Strain Wedge Model (SWM) in which the p-y curves are derived from the assumption of a wedge failure zone ahead of the pile, were used in this study. Both analyses were employed in a parametric study, calculating the piles' top lateral forces required to obtain given lateral displacements ranging from 0.5 in to 3 in (12.7 to 75.6 mm) in 0.5 in intervals. The results for the two methods are compared and examined against a database of laterally load tested piles. Factors affecting the performance of the analyses are discussed. Copyright ASCE 2009.