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.

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In this experimental campaign, concrete‐to‐concrete interfaces were examined under cyclic actions, crossed by postinstalled reinforcing bars or industrial steel screws. In addition, the effect of the embedment length and the roughness was investigated. It was observed that different failure modes occur, depending on the different connector types and embedment depths. The positive effect of roughness on the interface resistance was confirmed, but the results indicate that, for very high roughness values, the resistance may be smaller than for moderate values. It was also noticed that the behavior of interfaces crossed by mechanical anchors was less stiff in the ascending branch and exhibited a less steep falling branch. The extension of the project on testing thin overlays showed that the resistance was significantly affected in case of cyclic loading, suggesting that the use of any type of anchor in seismic conditions needs to be supported by adequate experimental evidence.

This paper discusses findings from an experimental program aimed at investigation of concrete breakout failure within the rebar end anchorage zone of reinforced concrete column-to-foundation joints, with columns located in proximity of foundation edge/s. A total of four tests on full scale column foundation joints are presented. In all specimens the column main reinforcement is anchored in the foundation using post-installed rebar technology. All connections are designed with the objective to trigger concrete breakout failure mode within the rebar end anchorage zone. Finite element analyses were used as a tool to design the specimens. The paper presents discussion of the test results within the framework of expectations outlaid during design of the test specimens. The effects of bending compression from column on the concrete breakout capacity under influence of foundation edges is the specific focus of the present investigation. It is shown that the direction of application of load on the column largely determines the effect of bending compression from column on concrete breakout capacity. The test data presented in this paper offers the necessary benchmark data on concrete breakout behavior in the case of reinforced concrete column foundation joints under influence of foundation edges. This test data along with insights from finite element analyses is employed to explore and possibly identify necessary modifications to the current state-of-the-art consideration of concrete breakout capacity for reinforced concrete connections.

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