A Strut-and-Tie Model Approach to Design Precast Column-to-Pile Shaft Member Socket Connections against Prying-Action Failure

This study presents a seismic design methodology for precast concrete column-to-pile shaft member socket connections. In designing such connections, the intent was to ensure that the plastic hinge occurs in columns while minimizing the damage to the pile shaft. To achieve this, a strut-and-tie model was developed to represent the force transfer mechanism within the connection region; this model served as the basis for efficient seismic design details, including shaft transverse reinforcement, column embedment length, and shaft size. The predictive accuracy of the strut-and-tie model was validated against both the experimental and finite-element analysis results for a wide variety of connection features. Upon validation, the strut-and-tie model was integrated into a step-by-step seismic design procedure and a case study was conducted to demonstrate the effectiveness of these procedures for determining suitable connection design details. Finally, a computer application with a graphical user interface was developed for the ease of implementation of the strut-and-tie model and reliable interpretation of its analysis results, making it possible to be used routinely in seismic design practice for precast column-to-pile shaft assemblies.