This paper presents the findings on the horizontal bearing performance of prestressed reinforced concrete (PRC) pipe pile group. Using field horizontal static load tests, we conducted an analysis and comparison of the horizontal bearing capacity among single piles, single pile caps, and double pile caps, while also investigating the influence of pile caps on the horizontal bearing capacity of the pipe piles. We used the ABAQUS software to compare and analyze the effects of pile group with different pile cap thicknesses, numbers of piles, and pile spacings. The findings show that the horizontal critical load of a double pile cap is twice that of a single pile cap, while the horizontal ultimate load of a double pile cap is 3.095 times that of a single pile cap. An increase in cap thickness increases the bending moment at the pile top. Conversely, there is a slight decrease in the horizontal bearing capacity of the pile group. As the number of piles increases, the mutual influence between adjacent piles decreases, leading to an enhancement in the overall bearing capacity of the pile group. The horizontal bearing capacity of pile groups augments with greater pile spacing. The findings provide a theoretical foundation and serve as a reference for the application of PRC pipe piles in highway bridge engineering.

Open-ended precast hybrid reinforced concrete (PRC) piles exhibit distinct vertical bearing behavior compared to closed-ended counterparts, primarily due to soil plug formation during installation. To quantitatively assess this difference, fiber Bragg grating sensors were embedded during pile fabrication, and vertical static load tests (SLTs) were conducted on piles P1–P6 with two end configurations and pile lengths. Experimental results for piles P1–P3 were validated through numerical simulations, and length optimization was performed. A parametric study was conducted to evaluate the effects of key geometric parameters on vertical bearing capacity. Results showed that, under identical pile length and stratigraphic conditions, open-ended piles exhibited lower ultimate bearing capacity (UBC), top settlement, and rebound rate than closed-ended piles. However, longer open-ended piles demonstrated significantly greater settlement and rebound than shorter counterparts. Optimization analysis indicated that the closed-ended pile could be reduced from 40 m to 35 m. With constant concrete volume, the D800t130 pile type yielded optimal performance, achieving the highest compressive coefficient (0.42) and material utilization rate (783.1 kN/m³). Both UBC and end resistance ratio increased with pile diameter. For closed-ended piles, diameter significantly influenced axial force distribution and side resistance, while wall thickness had minimal effect on end resistance but reduced side resistance. In contrast, open-ended piles exhibited greater sensitivity to both diameter and wall thickness in terms of axial force and lateral resistance. Inner wall friction was concentrated within twice pile diameters above the soil plug base, although its magnitude remained low. The height-to-diameter (h/D) ratio of the soil plug critically affected vertical bearing behavior. Compared to closed-ended piles, open-ended piles showed reduced lateral friction, with reduction coefficients ranging from 0.78 to 0.92. Notably, when diameter increased from 600 mm to 800 mm, open-ended piles outperformed as closed-ended piles in stiff plastic silty clay.