PSI - Issue 42

Jamal A. Abdalla et al. / Procedia Structural Integrity 42 (2022) 1223–1230 Abdalla et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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adhesive. The laminate properties of the CFRP and the mechanical properties of the epoxy adhesive, as provided by the manufacturer, are provided in Table 2.

Table 2. Mechanical properties of CFRP sheets/anchors and epoxy.

Elastic Modulus (MPa)

Ultimate tensile strength (MPa)

Elongation at failure (%)

Material

Density/weight Thickness (mm)

CFRP sheets/anchors (V-Wrap ™ C200H)

600 g/m2 1.11 Kg/L

1.02

73,770

1240 60.7

2.1 4.4

Epoxy adhesive (V-Wrap ™ 770)

-

2,760

2.4. Test setup

The specimens were tested under three-point bending tests (one-point loading) in a Universal Testing Machine (UTM) at a displacement-controlled rate of 1 mm/min. The load was applied mid-span of the beam as shown in Fig. 3. The shear span and overhang length were 850 mm and 150 mm, respectively. To monitor the strains in the U-wraps, one strain gauge was placed on each side of all the U-wraps at the locations shown in Fig. 3. The values recorded herein are the average values of the two strain gauges on each U-wrap. In addition, the strain in the concrete was monitored by mounting a strain gauge mid-span of the beam at the top of the flange, as shown in Fig. 3. The mid-span deflection was measured by placing a linear differential variable transducer (LVDT) mid-span at the bottom of the beams.

Fig. 3. Test setup (dimensions are in mm)

3. Experimental Results and Discussion The shear force-deflection curves are shown in Fig. 4. In addition, measured values of ultimate load ( P u ), deflection at ultimate load ( δ u ), corresponding total shear strength ( V n ), shear contribution of FRP ( V f ), strain in the FRP laminates at P u ( ε f ), and failure modes are summarized in Table 3. Shear strength of the beams was calculated as shear force at ultimate load using statics ( P u /2). In addition, shear strength of the control beam (BC) was considered as the shear contribution of concrete ( V c ) for all beams in this study due to nonexistence of stirrups in the test span of specimen BC. Furthermore, in accordance with most analytical models, shear contribution of FRP was calculated by subtracting V c from V n for each beam ( V f = V n - V c ).

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Fig. 4. Shear force-deflection curves of the tested specimens.