Development and Mechanical Property Analysis of a Novel Uplift Pile Incorporating Composite Anchors

This paper presents a novel design for uplift piles incorporating a composite-anchor system. The composite-anchor system consists of steel strands, a non-expansion grouting body, and a high-strength steel pile. The aim of this design is to enhance the mechanical performance, durability, and economic efficiency of uplift piles. To evaluate the performance of the new pile, three sets of full-scale load tests were conducted, focusing on their in situ capacity, deformation, and stress characteristics. Despite a significantly lower reinforcement ratio of 0.75% compared to conventional piles with a ratio of 3.84%, the new uplift piles exhibit an exceptional uplift bearing performance. The utilization of the lateral friction resistance of the lower pile body is significantly improved, leading to enhanced load distribution and stress transfer mechanisms. Furthermore, a numerical model was developed and validated against the experimental results, demonstrating its reliability in simulating the bearing characteristics of the new uplift piles. The multi-interface design of the composite-anchor system ensures the efficient transmission of internal forces induced by external uplift loads, resulting in an improved stress state within the pile body. Moreover, the multi-layer structure of the composite main bar enhances the durability of the uplift piles. In comparison to conventional piles, the new uplift pile design offers substantial advantages, including an 80% reduction in reinforcement ratio, a 65% reduction in reinforcement cage welding, a cost reduction of approximately 30%, and a shortened construction time by around 20%. These findings highlight the potential of the new composite-anchor-pile design to revolutionize the field of uplift pile applications, offering improved efficiency and effectiveness.