Numerical Simulation of Post-Yield Hysteretic Behavior of Lap-Spliced Reinforced Concrete Bridge Pier Walls Under Earthquake Loading

Reinforced concrete pier walls designed before the 1970s often incorporate lap splice in potential plastic-hinge regions. Previous experimental tests indicate that most of pier walls experienced post-yield lap splice failure, necessitating a modeling approach that captures not only lap splice strength but also deformation capacity. Although numerous modeling approaches for lap splice behavior have been proposed, limitations remain because (1) lap-spliced pier walls exhibit significantly different responses along their strong and weak axes due to high cross-sectional aspect ratios, and (2) experimental data on strong-axis behavior remain scarce for developing empirical equations. To address these challenges, this study introduces a numerical model to capture the post-yield hysteretic response of flexural-dominated lap-spliced pier walls by modifying the stress–strain relationship of longitudinal reinforcement. A dataset comprising 17 pier walls subjected to weak-axis loading and five rectangular column specimens was compiled to calibrate the numerical model. Linear regression analysis was employed to derive predictive equations for the model parameters. The accuracy of the proposed model was validated by predicting the hysteretic response of both strong-axis and weak-axis specimens excluded from the model development process. As an application, this study constructed the numerical model of bridges with pier walls with and without lap splice in plastic-hinge regions and compared their seismic demands. The results revealed that the presence of lap splice elevated the seismic demand of pier walls in terms of curvature ductility considerably.