Investigation on bond in post‐installed anchored bars and lap splices subjected to direct tension

Moment‐resisting monolithic connections between new and pre‐existing structural members are frequently used whenever existing reinforced‐concrete structures must be extended and/or strengthened. Overlapping post‐installed and cast‐in‐place bars is a common solution to provide reinforcement continuity. Nowadays, post‐installed bars with high‐performance mortars can reach higher bond strength than cast‐in‐place bars configurations. While higher performance could lead to shorter embedment lengths, uncertainties and constraints from design standards limit the potential for cost‐effective solutions. In this work, an experimental investigation on post‐installed lap splices is presented with some novelties in terms of test setup and specimen layout. The bond of a high‐performance injection mortar used in all specimens was assessed by means of tension tests. Lap length, concrete strength, and confinement by transverse reinforcement are the variable factors in the study of the load–slip behavior of the bars and the splitting resistance of the specimens. Results are in good accordance with the design formulas available in standards and empirical data published in the literature.