PSI - Issue 78

Sara Cattaneo et al. / Procedia Structural Integrity 78 (2026) 137–144

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3. Experimental results 3.1. Specimen BCJ-A The specimen BCJ-A had six post-installed rebars installed with adhesive A.

The concrete compressive strength at the time of the test was 27.6 MPa in the column and 27.5 MPa in the beam. The maximum loads were -210.7 kN (upwards) and +224.5 kN (downwards) both associated to the first cycle at a drift level of 40 mm. The damage developed progressively during cycles, with the first diagonal crack in the joint at a drift level of 10 mm (in both directions). The test was stopped at a drift level of 60 mm due to the significant strength degradation in positive direction. An evident detachment between the column and the beam was observed together with a wide damage on the column, both on the top surface (beside the beam) and on the lateral surfaces (Fig. 5). By removing the loose material on the top surface of the column, three small cones (height of about 50 mm with a diameter of 80 mm) were observed around the post-installed rebar. This suggests a combined cone-pull-out failure of the post-installed rebar. Figure 6 shows the load-drift graph.

Fig. 5. Specimen BCJ-A after failure.

100 150 200 250

-250 -200 -150 -100 -50 0 50

-80

-60

-40

-20

0

20

40

60

80

Load [kN]

Peak load 1st diagonal joint crack

Drift [mm]

Fig. 6. Load – drift.

The strain gauges placed on the longitudinal bars of the beam recorded significant values (above 1000  ) since the beginning of the test (Fig. 7), while strain gauges on the stirrups showed significant measurements starting from a drift of 10 mm (second cycle) (Fig. 8). At the same drift level, diagonal cracks developed in the joint core.