PSI - Issue 62

Francesco Bencardino et al. / Procedia Structural Integrity 62 (2024) 972–982 Francesco Bencardino/ Structural Integrity Procedia 00 (2019) 000 – 000

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4.2. Illustration of the intervention The designed FRP-based strengthening intervention is herein illustrated by means of photos documentation from Fig. 9 to Fig. 14. A total of four main phases were required in order to achieve properly the strengthening in a precise order, as follow: 1. preparation. Prepare the concrete surface to ensure proper bonding between the FRP material and the substrate. This involved cleaning the surface, removing loose concrete, and creating a rough profile by sandblasting and/or grinding.

2. FRP-plates installation for bending strengthening. 3. FRP-sheets installation for shear strengthening. 4. Finishing.

The application of a suitable adhesive or epoxy resin to the prepared concrete surface is a key-aspect being the strengthening bond-dependent. The resin serves as the bonding agent between the concrete and the FRP-material. At this scope it is fundamental to ensure proper mixing and application of the adhesive according to manufacturer guidelines to achieve a strong bond. The FRP-sheets or -plates need to be pressed to ensure effective contact and uniform bonding between the FRP-material and the substrate.

Fig. 9. Phase 1: preparation of the intervention surfaces: cleaning, chipping and levelling, corrosion inhibitors.

Fig. 10. Step 2: application of bending plates, I layer and II layer – CFRP-plate 120x1.4 mm.