PSI - Issue 84

Irene Matteini et al. / Procedia Structural Integrity 84 (2026) 677–685

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• Linear gain and Time Gain Compensation The wave velocity was set at 0.15 m/ns and 0.10 m/ns for asphalt and concrete respectively, as indicated by hyperbola fitting on the reflectors. The recorded profiles (B-scan) were then compiled into a 3D volume that was horizontally sliced (C-scans) to provide 2D maps of the key features at different depths. Given the limited documentation available of this structure, the objective of the project is on one hand to provide general information on the configuration of the bridge deck – including steel reinforcement layout, cover analysis, and overall thickness of the deck. In addition, the aim of this investigation is to establish a dataset of information to guide and assist the owners to do punctual interventions and assessment. 2.3. Survey Results Part I: The configuration of the bridge In the following section, through the data collected, it was possible to identify the key information of the bridge deck as follows: • Asphalt Thickness • Reinforcement Layout Configuration • Cover Asphalt Layer: Multiple layers of asphalt were detected from the scans. The recurring stratigraphy, illustrated in Figure 3 (B-scan), presents two different layers of asphalt with an indicative thickness of 10 and 15 cm detected above the concrete deck. The concrete deck is estimated to have a net thickness of 35 cm with two outer rebar layers.

Fig. 3. B-scan displaying the recurring stratigraphy.

Figure 4 provides a map of the shallow anomalies (1 to 3 cm) displaying a peculiar crack pattern in the asphalt layer, with three main cracks orthogonal to the bridge axis, close to the abutments and approximately at mid-span.