PSI - Issue 62

Manuel D’Angelo et al. / Procedia Structural Integrity 62 (2024) 9–15 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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4. State of conservation The state of conservation of bridges can widely vary depending on factors such as location, material of the bridge, maintenance practices, and exposure to environmental conditions. In the Guidelines, the level of defectiveness is one of the parameters that concur to the definition of the vulnerability level of the structural and foundational risk (Level 2). More specifically, the level of defectiveness of the whole structure is evaluated by taking into account the defectiveness of each structural element observed during visual inspections (during L1 activities) and assessing how it might impact the ability to withstand both traffic and seismic loads. For each element, the presence of a list of typical defects of that element and that particular material is checked during visual inspections. Each of the defects is associated with a weight (G), varying from 1 to 5: less serious defects have a weight of 1, the most serious defects have a weight of 5. For deck elements (arch, beams, etc.), typical G5 defects for bridges are spalling, corrosion, diagonal and transversal cracks, etc. For vertical elements (piers and abutments), typical G5 elements are scour, foundational movements, corrosion, and diagonal cracks. context. As the Warning Classes, the overall level of defectiveness is classified according to five levels, i.e., high, medium-high, medium, medium-low, and low. Figure 3 shows distribution of the level of defectiveness and the number of G5 associated to a specific structural scheme, for a sub-sample of bridges composed by 207 structures (Level 1). The large number of bridges in Umbria Region (see Figure 5) have been only censed at the time of the article submission. For the most typical structural schemes, i.e. arch, simply supported beams, and slabs, all the five levels of defectiveness are populated, with a clear preponderance of low defectiveness. On the other hand, rarer structural scheme (Half-joint and continuous beam, Maillart and tied-arch) tends to show more severe level of degradation. However, the low frequency of these type of bridges at the local level does not allow a robust statistic. Table 1 shows for each particular structural scheme the number of G5 recorded on average on a bridge, and the percentage of bridge declared in “critical condition”: for those structure, the level of defectiveness is automatically considered “high”. In this case, arch and simply supported beams show a net differenc e of number of G5 per bridge. However, this is quite obvious considering that the list of possible defects labelled as G5 are higher for simply supported beams in r.c and p.r.c. On the other hand, the two types of structures show the same percentage of bridges in critical conditions.

Fig. 5. Defectiveness levels percentages for each structural scheme