PSI - Issue 62

Gallipoli Maria Rosaria et al. / Procedia Structural Integrity 62 (2024) 940–945 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 1. (a) Schematic of configuration I on the deck (red dots: SARA array) and configuration II on the arch (green dots: Sentinel – Lunitek array), and sketch of foundation soil lithology; top-right: the three-directional acquisition reference system; grey arrow: direction of forward propagating waves; black arrow: direction of backward propagating waves when using the indicated reference stations; (b) Photos of the instrumentation used in this study: (1) Lunitek-Sentinel - GEO008 Matera side (Fig. 1a); (2) SARA velocimeter 01 placed on a quarter of the total deck length (Fig.1a).

Six eigenfrequencies were estimated using FAS and FDD, and the relative mode shapes were evaluated using FDD for both the deck and the arch. For the sake of brevity, only the main results for the deck are summarized in Tab.1 and Fig. 2. The 1 st mode of the deck at 0.76 Hz shows a major contribution in the vertical and a minor in the longitudinal direction (Fig. 2). The mode shape of the 2 nd mode at about 1 Hz shows larger displacements in the vertical direction, but with non-negligible values in the transverse direction, which means that the 2 nd mode of the deck is most likely a torsional mode. The 3 rd mode of the deck at f = 1.35 Hz is a mainly vertical bending mode. The 4 th mode shape of the deck at f = 1.50 Hz shows larger values in the vertical direction and non-negligible values in the transverse direction. The 5 th mode at f ≈ 2 Hz of the deck is mainly a vertical bending mode. The 6 th eigenfrequency (f = 2.1 Hz) is probably a vertical torsional mode, as confirmed by the complexity plots not shown here.