Response of free-headed segmental piles with mechanical joints to lateral loading

Segmental piles with mechanical joints(hereinafter, mechanically-jointed piles), as an improved pile type, have been widely adopted in construction projects. Due to their structural differences from conventional single piles, their mechanical responses diverge significantly, particularly under lateral loading. Gaps form at the mechanical joint between two single pile segments in mechanically-jointed piles, amplifying distinctions in mechanical response compared to conventional piles. To investigate the mechanical behavior of mechanically-jointed piles under lateral loading, this study develops a calculation theory for mechanical response based on the *m*-method-a standard approach for conventional single piles. The theory's feasibility is validated via numerical simulations. Results indicate that numerical simulation align closely with *m*-method calculations: pile head displacement error is 4.8%, rotation error 6.2%, maximum bending moment error 24.9%, and maximum shear force error 8.2%. Comparative analysis of conventional single piles and mechanically-jointed piles with free ends reveals that under lateral loading, mechanically-jointed piles exhibit approximately 30% larger pile head displacement and approximately 55% greater rotation than conventional piles, indicating reduced deformation resistance. However, the results indicate that the mechanically-jointed pile can effectively reduce the maximum bending moment in the pile shaft. This reduction suggests a potential for optimizing the pile design and enhancing its lateral resistance performance under certain conditions.