PSI - Issue 44

Matteo Canestri et al. / Procedia Structural Integrity 44 (2023) 2198–2205 Canestri et al./ Structural Integrity Procedia 00 (2022) 000–000

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substrate. The failure mode observed in all cases was debonding at the textile-to-matrix interface (Ascione et al., 2015), while the average bond strength σ lim at peak resulted equal to 1169 MPa (C.o.V. 16%).

Fig. 2. Single-lap shear tests: (a) test setup; (b) failure mode; (c) stress vs slip curves.

2.3. Uniaxial compression test setup Uniaxial compression tests were carried out by means of a hydraulic press, with capacity of 6000 kN. Specimens were equipped with various instruments to capture deformations in the vertical and horizontal directions (Fig. 3). Four LVDTs were placed close to the corners of the samples, in contact with the loading plate, to measure the specimens shortening. In addition, twelve potentiometers (three per side), with a gage length of 150 mm, were positioned to capture its horizontal expansion. The load was applied monotonically up to failure and the post-peak behavior was controlled without a closed loop system by imposing the machine head advancement. With the intention to identify the entire post-peak behavior of the specimens, all the tests were conducted up to a conventional failure, established as the 20% of the maximum recorded force.

Fig. 3. LVDTs and potentiometers layout.

3. Experimental results The experimental results of the monotonic compression tests are reported in Table 2, in terms of maximum load, stress value at peak and corresponding vertical and horizontal deformations. In more detail, vertical deformations ε v of all samples were derived as the average value of all the vertical LVDTs readings, divided by the corresponding gauge length (total height of the sample). Horizontal deformations ε h were obtained by averaging the readings of all the potentiometers positioned on the four sides of the specimen (150 mm gauge length). The increase in load bearing capacity of the columns, due to the application of the SRG reinforcing layers, was evaluated as the ratio between the maximum load of the strengthened samples and that of the unreinforced specimen. In general, it can be stated that