Experimental assessment of battered pile configurations under seismic loading: focus on negative inclinations

Pile foundations play a crucial role in maintaining structural stability during earthquakes. This study addresses the underexplored behavior of negative battered piles under seismic loading. An experimental investigation was conducted on 2×2 pile groups embedded in sandy soil with a relative density of 30%, using a shaking table to simulate seismic events. The study evaluated the seismic response of front-row piles battered at -5°, 0°, and +5°, under input motions from the El Centro and Kobe earthquakes. The aim was to assess the comparative performance of negative battered piles relative to vertical and positively battered piles in terms of lateral and vertical displacement. The physical model tests revealed that negative battering significantly increases pile displacements under seismic loading. Specifically, shifting the batter angle from 0° to -5° caused a 315.93% increase in maximum lateral displacement, whereas a change from 0° to +5° resulted in only a 3.37% increase. Similarly, the maximum vertical displacement increased by 43.11% with negative battering, while positive battering led to a 2.33% reduction in lateral displacement. These findings demonstrate the adverse effects of negative battering on seismic performance and highlight the importance of considering batter angle orientation in pile group design for earthquake resistance. Overall, this research provides new experimental insight into the behavior of negatively battered piles, emphasizing their vulnerability under seismic loading and contributing valuable data to guide geotechnical and structural design in sandy soils.