Numeric Analysis on Shear Behavior of High-Strength Concrete Single-Keyed Dry Joints with Fixing Imperfections in Precast Concrete Segmental Bridges

摘要

Fixing imperfections in keyed dry joints between the concrete segments compromise the performance of precast concrete segmental bridges (PCSBs), which needs to consider carefully. In this study, a finite-element model on high-strength concrete single-keyed dry joints in PCSBs was established and validated by experimental results. Parametric studies on fixing imperfections in key, concrete strengths, and confining pressures were carried out based on that model. The numeric results included crack patterns, load–displacements and shear strength. Fixing imperfections—especially at lower surface of keys—reduced shear strength of single-keyed dry joints by the different shear transfer mechanism. Higher confining pressure and concrete strength improved the shear strength, but they mitigated and aggravated the effect of fixing imperfections at lower surface of key on shear strength, respectively. Compared with simulating results, AASHTO standard overestimated the shear capacity of single-keyed dry joints with fixing imperfections at lower surface of key by up to 0.602–22.0%, but greatly underestimated that of the rest. A modified formula with a strength reduction factor was proposed. For six experimental three-keyed dry-joint specimens and 30 numeric single-keyed dry-joint specimens with or without fixing imperfections, the average ratio of code predictions to experimental results was 90.4% and 81.6%, respectively.