Analysis and optimization of horizontally loaded prestressed concrete square piles with variable reinforcement configurations

To reduce material cost without compromising safety, this study proposes an optimized variable-reinforcement configuration for prestressed concrete square piles, where the lower segment uses a reduced reinforcement ratio. A 3D finite element model, validated against field tests (peak moment error < 7.8%), simulates the pile behavior under horizontal and combined loads across varying soil conditions. The results demonstrate that bending moments and shear forces in the lower pile segment (below 6.2 m depth) are negligible (< 10 kN·m and < 5 kN), even under a 260 kN lateral load. This pattern remains consistent across different soil types, pile lengths (15–30 m), and combined loading scenarios. Consequently, reinforcement in the lower segment can be safely reduced, yielding an estimated material saving of 15%–20%.