Abstract
This study builds upon previous experimental research on deep four-pile caps by performing numerical verification and extending the investigation through parametric analysis using ABAQUS (FEM). The numerical model was calibrated using results from a control specimen tested in the experimental program, showing strong agreement and validating the reliability of (NLFEA). The differences between the experimental and FE models were limited to 2.85% for the ultimate load and 4.13% for the mid-span deflection, respectively. A numerical study, using the calibrated numerical model, evaluated three reinforcement strategies: (1) top steel mesh (TM); (2) lateral Hoop (Lateral hoop series); and (3) strut reinforcement (ST). Compared with the control specimen, the TM (Top Mesh series) increased the ultimate load by about 1.3–5% and slightly improved post-peak ductility, the HOOP-series enhanced the ultimate load by up to 32.7% and significantly increased failure deflection, while the ST-series led to a 6–7.2% increase in ultimate load and reduced damage concentration along the compressive strut., The results demonstrated that optimized reinforcement layouts significantly improved load capacity, delayed crack propagation, and reduced brittle failure tendencies. Lateral reinforcement notably enhanced post-peak resistance, while compressive strut reinforcement promoted uniform stress distribution and structural integrity. Among the investigated reinforcement strategies, lateral hoop reinforcement provided the greatest combined enhancement in ultimate load and ductility compared with the reference pile cap.The results underscore the critical role of reinforcement configuration deep pile cap design, particularly for addressing shear and compressive maximum stresses. The findings provide practical recommendations to optimize configurations enhance durability and performance..