PSI - Issue 64

Isabella Mazzatura et al. / Procedia Structural Integrity 64 (2024) 114–121 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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2.1. Specimens Six specimens were realized, three following the scheme of Fig. 2a, and three of Fig. 2b. The main difference consisted in the use of strands for the first three and of dywidag bars for the others, being these two systems the main historically employed in PT structure. Concerning the overall geometrical dimensions, there were only slightly differences (Fig. 2). The first group provided six ducts, while the second eight. The specimens were realized for wider research involving the detection of ungrouted regions of different dimensions through the PT ducts. Therefore, the other differences involved the extension and the typology (water or air) of the defects and the material of the duct (plastic or metal). However, these aspects are not relevant for the aim of the present research and, thus, are not reported in the following.

a) b) Fig. 2. Dimensions of the specimens and location of the ducts. a) shows the specimens providing strands, while b) the ones providing bars.

2.2. Execution of the tests The tests are executed in 4 different modalities since the objective of the campaign is to discover the influence of the execution on the test output with the objective to select the best procedure when applied to real bridges. On each wall and side, the test is carried out on three different lines (A, B, and C, in Fig. 3), equally spaced. The following configurations are considered: • Configuration I: the direction of the test is from the bottom to the top of the wall and the instrument is in the straight position. • Configuration II: the direction of the test is from the top to the bottom of the wall and the instrument is in the inverted position. • Configuration III: the direction of the test is from the top to the bottom of the wall and the instrument is in the straight position. • Configuration IV: the direction of the test is from the bottom to the top of the wall and the instrument is in the inverted position.

a) d) Fig. 3͘ Configurations of the test. a) Configuration I, b) Configuration II, c) Configuration III, and d) Configuration IV. b) c)