PSI - Issue 44

Annalisa Franco et al. / Procedia Structural Integrity 44 (2023) 2246–2253 Author name / Structural Integrity Procedia 00 (2022) 000–000

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Contrarily to what exhibited by the yarns of system “F”, by observing the load-strain curves shown in Fig. 6, no evident differences arise from the curves obtained at 2 mm/min and the ones at 200 mm/min when testing the yarns of system “G”.

(a)

(b)

Fig. 6. Load-strain curves obtained by testing the yarns of system “G” at: (a) 2 mm/min and (b) 200 mm/min.

Finally, the stress-strain curves obtained by testing the grids in their warp direction are shown in Fig. 7. Here, the stress is obtained by dividing the load recorded during the test by the area of the cross section of bar, reported in Tab. 1 for both systems, while the strain by dividing the displacement of the crosshead, recorded during the test, by the distance from the clamps, which is 345 mm for system “F” and 410 mm for system “G”. All the specimens exhibit an elasto-brittle behaviour, with an extremely repeatable stiffness for both systems.

(a)

(b)

(c) (d) Fig. 7. Stress-strain curves obtained by testing grids in their warp direction: (a) system “F” at 2 mm/min; (b) system “F” at 50 mm/min; (a) system “G” at 2 mm/min; (b) system “G” at 50 mm/min.

4. Discussion and conclusions Strengthening through FRP grids embedded in inorganic matrix (CRM) is becoming an ever-increasing and effective technique for the retrofitting of masonry structures. An experimental campaign was carried out with the aim