PSI - Issue 37

Ghusoon S. Alshami et al. / Procedia Structural Integrity 37 (2022) 367–374 Alshami et al./ Structural Integrity Procedia 00 (2021) 000 – 000

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Fig 3. Strengthening procedure. (a) surface preparation; (b) notch grinding; (c) anchor hole drilling; (d) primer and epoxy mixture preparation; (e) applying primer on concrete surface after cleaning; (f) installing impregnated CFRP laminate and anchors; (g) using groove rollers to remove air bubbles. 3.4 Test Setup All prisms were tested under two-point loading using Matest concrete flexural machine at a displacement controlled mode rate of 0.25 mm/min. Figure 4 shows the schematic of the loading test setup. To monitor the strain in the CFRP laminate during loading, one strain gauge was placed on the CFRP close to the center of the strengthened prisms, as shown in Fig.5.

Fig.4. Test Setup.

(a)

(b) Fig. 5. Strain gauge location on: (a) unanchored prism; (b) anchored prism.

4. Results and Discussion A total of six prisms were tested under four-point bending. Prisms C and L1 were considered as control beams and benchmarks for beams AL1-E50, AL1-E75, AL1-E100, and AL1-E125. Table 4 presents all results related to ultimate load ( P u ), mid-span deflection at ultimate load ( δ u ), ultimate strain in the CFRP laminates ( ε frp ), percent increase of ultimate load ( P u ) over the control specimen, percent increase in mid-span deflection at ultimate load compared to the control unstrengthened specimen (C), and percent increase in mid-span deflection at ultimate load compared to the control strengthened unanchored specimen (L1). Load-deflection response curves at midspan, percentage increases in ultimate loads with respect to C and L1 specimens, and ultimate strain values are illustrated in Figs. 6-8, respectively. Moreover, different failure modes were witnessed and are presented in Fig.9.