This thesis investigates the impact of confinement on the structural performance of Concrete-Filled Steel Pipe (CFSP) pile to concrete cap connections in the absence of dedicated force transfer provisions such as dowels or shear rings. Current Eurocode guidelines provide no explicit framework for confinement in partially loaded areas, resulting in uncertainties in design. The research combines theoretical modelling, drawing on Mander’s confined concrete model and the Dual–Wedge Stress Field (DWSF) approach of Markič et al., with a finite element case study to evaluate confinement mechanisms. A quasi-non-linear analysis was implemented to approximate peak concrete strength, supported by analytical formulations and parametric scripts. The findings confirm that confinement significantly enhances bearing capacity and stress transfer in CFSP pile–to–cap connections, with the FEA substantiating several features of the DWSF model while also highlighting limitations in reinforcement activation and stress redistribution. Overall, the study demonstrates that confinement effects are decisive for structural performance and should be explicitly considered in design practice to achieve reliable and efficient CFSP connections.
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