Abstract The shear performance of epoxied joints is critical to the structural integrity of precast concrete segmental bridges (PCSBs). However, prevailing design formulas, predominantly developed for dry joints, often yield significant and unsafe overestimations of the capacity of epoxied joints. This study presents a combined experimental and theoretical investigation to elucidate the fundamental shear transfer mechanisms and failure modes of both dry and epoxied joints. Experimental results reveal a distinct mixed‐mode failure in epoxied joints, involving cohesive failure within the adjacent concrete substrate, adhesive debonding at the interface, and cohesive failure of the epoxy itself—a mechanism overlooked by existing models. A comprehensive database of 212 test results was utilized to evaluate six established analytical models, systematically revealing their limitations in predicting the strength of multi‐keyed epoxied joints due to unaccounted shear distribution effects. To address this gap, an improved analytical expression is derived based on Mohr's circle theory, explicitly integrating the contributions from both the concrete keys and the epoxied interface. The proposed model demonstrates exceptional accuracy, with a mean predicted‐to‐experimental ratio of 0.96 and a standard deviation of 0.12, signifying unbiased and reliable predictions. Furthermore, the model is successfully extended to predict the shear‐flexural capacity under combined loading scenarios incorporating joint opening effects, demonstrating its broad applicability. Finally, its application is successfully demonstrated through a case study of a full‐scale bridge girder, proving its direct utility for the design and assessment of PCSBs.
Zou et al. (Thu,) studied this question.