Behavior of Battered Piles under Lateral Loads in Sandy Soils-Paper

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The paper presents a modified Strain Wedge (SW) model for predicting the response of long battered piles under lateral loads in sandy soils. Unlike conventional methods, which estimate battered-pile behavior by applying a multiplier to the p-y curves of an equivalent vertical pile, the model derives p-y curves directly from soil and pile properties, pile geometry, and batter angle.<br /><br />The method represents soil–pile interaction through a three-dimensional passive soil wedge. It accounts for the direction and magnitude of batter, soil stress and strain, sand properties, and pile stiffness. The pile and surrounding soil are divided into segments, and the calculated soil response is coupled with a beam-on-elastic-foundation analysis to estimate pile-head deflection and bending moment.<br /><br />Predictions were compared with full-scale tests, centrifuge tests, and other pile-load-test results. The comparisons showed generally good agreement with measured lateral responses and bending moments.<br /><br />The analysis confirms that batter direction strongly affects performance: negative-batter piles are stiffer and generally have greater lateral capacity than vertical piles, while positive-batter piles are more flexible and have lower capacity. The influence of batter varies with sand relative density and diminishes with depth. In the study’s example, a pile with a −20° batter was 30–60% stiffer than a vertical pile, depending on sand density; a positively battered pile was 45–55% softer.<br /><br />The authors conclude that battered-pile response and p-y curves should be evaluated using batter angle and site-specific soil and pile properties, rather than relying on a fixed multiplier applied to vertical-pile curves.

Keywords

Strain Wedge model

battered piles

lateral loads

sandy soils

p-y curves

soil-pile interaction

pile deflection

bending moment

passive soil wedge

beam-on-elastic-foundation