PSI - Issue 11

Esequiel Mesquita et al. / Procedia Structural Integrity 11 (2018) 138–144 Author name / Structural Integrity Procedia 00 (2018) 000–000

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a)

b)

c)

Fig. 2- RC specimen, a) before and b) after concrete fulfillment and c) the data acquisition system employed during the experimental setup.

For application in old RC structures monitoring, a concrete layer of 10.00 cm x 10.00 cm should be extracted in the area of interest till the reinforcing bar be visible. After that, the reinforcing is cleaned and a fine layer of the resin is applied for fixing the sensor. Considering that the sensor is completely fixed, the slot should be filled by concrete again. The pull-out testing was performed according to descriptions of the Annex D of the EN 10080 (European Standard, 2005), and the details of the equipment used are shown in the Figure 3a). For this testing the RC specimen was positioned in centralized form and the vertical specimen displacement was restricted by employment of two metallic plans, fixed in the inferior beam of the steel-frame. The rebar was fixed to an actuator, and two linear variable differential transformers (LVDTs) were positioned at the inferior surface of the RC specimen, as detailed in Figure 3c), to measure the relative movement between the concrete and the rebar, providing another comparison measurement, although outside the specimen.

Fig. 3- Experimental setup of the pull-out testing: a) details of the pull-out testing equipment, b) photography of the testing carrying-out and c) positioning of the LVDTs.

4. Results Pull-out test was carried out, according by the previous section, on the concrete sample with the FBG optical sensor embedded, and the collected curve presents a linear elastic part with different levels of displacement. Figure 4 shows the imposed force, along time, collected from the testing machine.