This example is based on the full-scale lateral load test of a 3 × 3 pile group reported by Christensen (2006). The test site comprised alternating sand and clay layers. The piles were steel pipes with an outer diameter of 0.324 m and a wall thickness of 0.0095 m. In the direction of loading, the piles were spaced at 5.65D (1.83 m) centre-to-centre, and 3.29D (1.07 m) centre-to-centre perpendicular to the loading direction. Each pile had an embedded length of 12.8 m, with the