PSI - Issue 78

Francesco Bencardino et al. / Procedia Structural Integrity 78 (2026) 1396–1403 Author name / Structural Integrity Procedia 00 (2025) 000 – 000

1401

6

0 + . / 8 − = 0 + .8 /− + /−

(2)

where s y displacement values were analytically estimated by considering, for each direction, an energy equivalence between the area underneath the experimental skeleton curve and an idealized elastic-plastic response obtained by considering 80% F +/- max as strength threshold.

Table 2. Experimental results

F max [kN]

s + max [mm]

s max [mm]

s + 0.8 [mm]

s 0.8 [mm]

s + y [mm]

s y [mm]

μ + [-]

μ max [-]

μ + [-]

μ 0.8 [-]

F + max [kN]

max

0.8

Specimen ID

BM-B1-M1#1 239.47 194.73 24.03 23.94 27.21 25.91 13.52 10.16 1.78 BM-B1-M2#1 119.10 133.52 12.98 13.98 16.75 16.36 5.10 2.59 2.55 BM-B2-M1#1 236.98 214.48 18.66 23.94 23.87 24.18 7.88 12.71 2.37 BM-B2-M2#1 155.23 188.26 25.95 21.99 25.80 25.67 6.26 13.95 4.15 176.59 241.55 35.99 31.98 35.76 34.23 7.07 115.18 120.90 22.30 23.02 23.91 23.58 18.72 12.71 1.19 9.60 5.09 BM-UR BM-S-M1#1

2.36 2.01 2.55 5.40 3.28 6.32 1.88 3.03 1.90 1.58 4.12 1.84 3.33 5.06 3.57 1.81 1.28 1.86

Fig. 4 shows that the highest performances in terms of both strength and ultimate displacements were recognized in specimens strengthened with M1 mortar, regardless of fabric or strengthening layout employed (Fig. 4c). The highest improvements in terms of ductility were achieved in BM-B2-M1#1 specimen; however, the maximum values of strength were observed in specimens comprising B-FRCM reinforcement with both strengthening layouts.

100 150 200 250

100 150 200 250

b)

a)

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

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

-40 -30 -20 -10

0

10

20

30

40

-40 -30 -20 -10

0

10

20

30

40

Force [kN]

Force [kN]

B1-M1 B1-M2 BM-UR

B2-M2 B2-M1 BM-UR

Displacement [mm]

Displacement [mm]

100 150 200 250

100 150 200 250

c)

d )

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

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

-40 -30 -20 -10

0

10

20

30

40

-40 -30 -20 -10

0

10

20

30

40

Force [kN]

Force [kN]

B1-M1 B2-M1

B1-M2 B2-M2

S-M1 B2-M1 B1-M1 BM-UR

S-M1

URM

Displacement [mm]

Displacement [mm]

Fig. 4. Comparisons between cyclic response or skeleton curve (d) of specimens strengthened with different matrices and basalt fabric on one (a) and both (b) sides and among FRCM systems made with M1 matrix and different strengthening layouts/fabrics (c).

Unlike the case of M1 mortar, efficacy of reinforcement got improved when going from B1 to B2 strengthening layout when M2 mortar was used. Indeed, the peak value of shear forces increased by about 25%, while the ultimate value of horizontal displacement went from 17 to 26 mm.