PSI - Issue 64

Annalisa Napoli et al. / Procedia Structural Integrity 64 (2024) 975–982 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

978

4

External Strengthening with steel plate

a) MF Plate (no bonding with epoxy)

b) EB plate w/o anchors

steel plate

anchors

steel plate

L p

L p

c) EB plate w/ end anchors

d) EB plate w/ distributed anchors

steel plate

anchors

L p steel plate

anchors

anchors

L p

e) EB plate w/ studs

f) EB plate w/ L-shape anchors

L shape anchorage

steel plate

studs

steel plate

L p

Fig. 2. Schematic of the external strengthening with steel plates: (a) mechanical fastening (MF); (b) externally bonding (EB) w/o anchors; (c) EB w/ end anchors; (d) EB w/ distributed anchors; (e) EB w/ clamps; (f) EB w/ L-shape anchors.

Figure 3a provides information about the shape of the cross-section of the tested beams. As shown, 73% of the database consists of rectangular members with height -to- width (h/b) ratio ranging between 1.25 and 2.5; h/b = 1.5 was the most considered value. To this purpose, Figure 3b shows the distribution of members with rectangular cross section by the h/b ratio. Among the 20 beams with T-shape cross section, 19 were tested by the same researcher (Salman 2015) and were characterized by height - to - web width ( h/b w ) equal to 2, and by a flange 450 mm wide and 68 mm thick; the remaining T-beam was tested by Ozbek et al. (2016) and was characterized by h/b w =2.5, flange 450 mm wide and 68 mm thick.

30

Cross-section

Rectangular specimens: #53

Rectangular T-shape

25

h

16 (22%)

20

MF plate

15

b

37 (51%)

10

EB plate

20 (27%)

5

Number of specimens

EB plate

0

1

1.25

1.5

1.75

2

2.25

2.5

h/b ratio

(a)

(b)

Fig. 3. Distribution of RC beams based on the cross-section shape (a); distribution of rectangular members based on the heigh/width ratio.

The graphs in Figure 4 provide the values of the mechanical percentages of internal (tensile) reinforcement (  s ) characterizing the 57 beams strengthened with EB system (Fig. 4a) and the 16 beams strengthened with the MF system (Fig. 4b); the ratios between the mechanical percentages of external (steel plate) reinforcement (  r ) and  s are also reported. The parameters  r and  s are given by: = ∙ℎ ∙ , ; = ∙ ℎ ∙ , (1)