PSI - Issue 64

Paula Folino et al. / Procedia Structural Integrity 64 (2024) 1452–1459 Folino et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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in dotted lines correspond to the unjacketed beams, in dashed lines with double dots to the 60 mm thick SCHSC U jacket, in solid lines to the 30 mm thick SCFRHSC U-jacket, and dashed lines to the 60 mm thick SCFRHSC U-jacket. In all cases, the thickest lines represent cases where a rough interface surface was considered, and the thin lines represent cases with untreated surfaces. It is noteworthy that for specimen V72, a significantly reduced load was obtained due to the misalignment of the hydraulic loading jack.

Table 7. Beam tests results. Specimen

Jacket Width Unjacketed Unjacketed Unjacketed

Concrete Type

Surface Preparation

Peak Load [kN]

V69 V70 V90 V79 V80 V73 V86 V88 V78 V83 V87 V68 V75 V72 V74

- - -

- - -

47.8 50.3 47.5

60 mm 60 mm 30 mm 30 mm 30 mm 30 mm 30 mm 30 mm 60 mm 60 mm 60 mm 60 mm

SCHSC with reinforcing bars SCHSC with reinforcing bars

Rough Rough Smooth Smooth Smooth Rough Rough Rough Smooth Smooth Rough Rough

116.7 130.1

SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC SCFRHSC

83.7 84.4 87.0 88.9 88.7 91.4 98.4

105.7 88.9 117.5

Figure 2. TPB tests on jacketed and unjacketed beams: Load vs. Midspan deflection curves.

4. Results Analysis and Discussion Reference beams without jackets reached peak loads of around 48.5 kN, with a very brittle shear failure occurring after the peak. Fig. 3(a). shows an example of the tested beams, where only one shear crack can be observed. The jacketed beams with SCHSC and reinforcing bars showed the highest maximum load, with a mean value of 123.4 kN and presented a quasi-ductile failure with two main symmetric cracks as shown in Fig. 3(b). No detachments of the jacket were observed. In Figure 2 it can be observed that after the formation of the first crack at a deflection of approximately of 7 mm, there is a gradually decrease in stiffness. The jacketed beams with SCFRHSC achieved a mean peak load of 87.5 kN for the 30 mm thick reinforcements and 102.6 kN for the 60 mm thick ones. It is worth noting that increasing the thickness of the jacket did not lead to a proportional increase in strength and showed signs of detachment in cases of smooth surfaces. Although in all these cases failure was localized presenting a single crack near the mid-span (Figs. (a) and (b)), the addition of fibers