Investigation on the effect of reinforcement on the bond anchor in bridge beams

Bond anchors are extensively employed in bridge retrofitting, such as steel member connections and external prestressing, with tension being a primary loading condition. Reinforcement in substrate concrete significantly affects the tensile performance of anchors, yet its impact on failure modes and capacity remains insufficiently studied. This paper investigates the tensile behavior of bonded anchors through pull-out tests, examining embedment depth, reinforcement spacing, rebar diameter, and concrete cover thickness across 30 specimens. Results demonstrate that reinforcement substantially influences failure modes and tensile capacity, transforming concrete cone shapes from conical to conical-frustum hybrids with reduced radii. Tensile capacity improved by 3.78%-33.65%, with reinforcement spacing and embedment depth being more influential than rebar diameter or cover thickness. Further, the study results reveal reinforcement’s dual role: affecting concrete cone failure through spatial configuration while providing passive confinement under bonding failure. This study presents a comprehensive experimental investigation that significantly expands upon prior research regarding the reinforcement effect on bond anchors, and these findings offer practical design references and establish a foundation for further research on anchor reinforcement effects.