PSI - Issue 62

Alberto Contardi et al. / Procedia Structural Integrity 62 (2024) 81–88 Contardi A., La Fortezza F./ Structural Integrity Procedia 00 (2019) 000–000

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The indicated formula, although quite simple from a conceptual point of view, cannot be used yet due to the unavailability in current literature of practical procedures allowing the calculation of all the indicated parameters without uncertainties. While the costs of the interventions could be easily estimated in a parametric way even without carrying out preliminary complete projects, it would be important to develop two lines of research relating to the calculation of the probability of collapse and of economic and social costs and damages. The focus of the present article is on the second line of research, related with the failure costs of the bridges. 3. Damage estimation The most delicate and most complex part of the method is the determination of   , since the uncertainties involved are many and the values of these parameters may significantly impact on the results of the calculation. Each damage can be estimated as the sum of the following contributions, as already shown in Bulletin FIB 80: • Cost of replacing the collapsed structural part. • Cost of infrastructure disruption. It can be considered as the sum of the costs for the managing company (economic damage in term of missing payments, applicable to the toll road), and of the economic losses due to non-availability or malfunction of the structure for the whole community. • Social consequences (costs of injuries and fatalities). • Unfavourable environmental effects and damages to areas underneath. • Psychological effects (loss of reputation). The greater the importance and exposure of the bridge, the greater the damage will be. It should be emphasized that this estimate is a function of the robustness of the structure since many damages, as will be evident later, depend on the length of the collapsed part of the deck. It should also be noted that, for each limit state, its own economic impact is assigned, which can be very different from that of the other limit states. For example, the damages associated with the breakage of a part of slab is much less than those related to the breakage of a girder. In the next chapters many evaluations of the possible costs are reported. These figures are calculated for Italy and for 2023, where not otherwise specified, but with the same type of reasoning it should be possible to estimate the figures also for other countries. For the case study, it has been necessary transpose older costs to 2023 using the data provided by the Italian institute of statistic ISTAT.

3.1. Costs of restoration works

To estimate the costs of every kind of restoration works on a generic bridge, we have so many past projects available that can be used for this scope. In this study we propose the parametric costs shown in the following table, for every square meter of the deck:

Table 1. Costs of restoration works

Type of work

€/mq 1000 2500 3600

Remaking of concrete surfaces

Repairing and reinforcing beams and piers

Complete rebuilding of the deck

It is important to note that usually, if the height of the piers is not excessive, the first two types of work can be conducted without interrupting or disturbing the flow of traffic. Instead, the demolition and reconstruction sites could cause little delays to users, that should be taken into account adding to the cost shown in the previous table the figures calculated with the methods reported in the following chapters.