PSI - Issue 62

Anna Rosa Tilocca et al. / Procedia Structural Integrity 62 (2024) 1043–1050

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A.R. Tilocca et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 1. (a) Satellite image, (b) horizontal beam cross-section and (c) vertical columns cross-section.

In particular, a relevant onsite activity has been carried out, voted to verify the reliability of principal information, such as exact geolocation, technical declarations, principal dimensions contained in the design documents, use classification and kind of environmental conditions in addition to the technical data like traffic, use limitations, strategicity and/or presence of alternative way. It is important to understand that more of these information are designed for road/highway bridges and not directly applicable to a railway bridge without relative interpretations, here descripted in the following paragraphs. 4. Level 1: specific onsite visive inspections for defects evaluation and current state of railway bridge During the onsite inspections, an accurate photograph and geometrical relief has been carried out, including an evaluation of the current state of the structures, finalized to check and identify defects and degradation phenomena through apposite tables. Filling out the forms, permits also the estimation of intensity coefficient k 1 and extension coefficient k 2 of each one defects, with 3 different ranges: < 20%, 20÷50% and 50÷100%. The degradation level of defect ranging between low , medium-low , medium , medium-high and high . Therefore, using defects tables is also possible to detect the presence of “critical elements”, whose possible malfunctions can significantly affect the global structural behavior of the viaduct in question, or the elements or conditions for which the presence of an advanced state of degradation must be reported immediately. In our case study, railway bridge, as it possible to see in Figure 2 some different defects that it was possible to detect on columns, shoulders, beams and restraints are reported. In detail, with different intensity and extension indicators, the principal defects observed were the presence of active/passive humidity and traces of drainage with the presence of deteriorated concrete (Figure 2 , Figure 3b), vertical and horizontal cracks in correspondence of stirrups/rebars (Figure 2 , Figure 3a,c), detachments of concrete cover or insufficient concrete cover thickness with relative oxidation of the reinforcing bars (Figure 3c). Furthermore, sometimes along the horizontal elements of the bridge, especially on the header surfaces and on the reinforced concrete shoulders, were revealed water stagnations, due to the high degradation of neoprene joints between contiguous spans (Figure 3b). Concerning to the restraints, rebars oxidation were the principal defect relevant to supports (Figure 4 ) while for the accessory’s components, that not directly modify the total index of current state degradation, was possible to identify ballast on security way, closed drains and joint damaged.

Figure 2. Widespread defects on structural elements: Vertical structures.