PSI - Issue 44

Marta Del Zoppo et al. / Procedia Structural Integrity 44 (2023) 2158–2165 Del Zoppo et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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3.2. Single-side FRM configuration (FRM_1S) The wall specimen strengthened on one side with the FRM system exhibited a failure mode similar to the one occurred in the URM wall. Indeed, the development of a major crack two courses below the upper loading roller is observed in the FRM layer of the specimen (Fig. 5a). In terms of deformed shapes, the records show that out-of plane displacements have a higher magnitude at the mid-span of the wall even after the crack opening (Fig. 5b). This is probably related to the different location of the crack, which developed on the second bed joint starting from the loading roller (i.e., at a higher distance from the top line of LVDTs with respect to the URM panel). Indeed, after the first cracking of the FRM, the short glass fibres crossing the crack start working according to the “bridging” effect, as shown in Fig. 5c. In terms of capacity, the specimen reached a peak load of 43 kN, as visible from the force displacement curves reported in Fig. 5d for each line of LVDT records. (a) (b)

(c)

(d)

Fig. 5. (a) FRM_1S specimen, (b) deformed shapes, (c) fibres crossing the crack, (d) capacity curves.

3.3. Double-side FRM configuration (FRM_2S)

The wall strengthened on both sides with the FRM system also exhibited a flexural failure mode with the occurrence of the cracking in the bed joint immediately below the loading roller, as previously observed for the URM wall.