Influence of Sectional Depth on Structural Behavior of Bridge Pier Caps

A parametric study using finite-element (FE) analysis was conducted over a range of sectional depths to investigate the effect of the pier caps' sectional depth on structural safety and serviceability for pier caps with a simple determinate strut-and-tie models (STMs) design. The influence of sectional depth on the shear strength of the pier caps was also analyzed using pier caps with over-reinforced flexural rebar inducing shear failures. Analytical studies using determinate STMs showed that the amount of vertical shear reinforcement did not change regardless of the sectional depth of the pier cap. In contrast, the FE analysis suggested that excessive sectional depth could lead to overly conservative shear designs. In addition, the FE analysis showed that crack serviceability could be efficiently satisfied by constraining the pier caps' minimal sectional depth. Based on the FE analysis, design guidelines for simple determinate STMs were proposed to determine efficient sectional depths in pier cap design.