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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Table 6. Congestion costs in €-cent 2016 /km per vehicle

State of road traffic

Motorway

Other roads

Over capacity

22.3 10.7

45.2 23.5 10.5

Cars

Congested

Near capacity Over capacity

4.4

93.6 45.2 18.5

157.2

Trucks

Congested

81.5 36.5

Near capacity

3.3. Social consequences As cost per casualty, the DG MOVE Handbook in table 7 proposes for Italy 2888866 (human cost) + 354695 (production loss) + 2672 (medical costs) + 1873 (administrative costs) ≅ 3250000 € (2016). Here the costs of injuries are overlooked. Bulletin FIB 80 (chapter 3.3.2.2.) contains a very simple formula to estimate the probability of casualties as a function of the length of the collapsed structural part: the number of victims is calculated as =0.09 ∙  , where  is the collapsed length. A correct formula should take into account also the average daily traffic, the height of the bridge, the average travel speed and should depend also on the type of the limit state (if the traffic loads are decisive for the collapse, the probability that some users are involved is much greater); it could be an interesting theme for future researches. However, if better studies are not available, the Bulletin FIB 80 formulation could be used. It is important to remember that Bulletin FIB 80 also stated that in developed countries it is not accepted that the probability of becoming the victim of a structural failure could be larger than the normal probability of dying as a result of an accident (chapter 3.3). This requirement (not considered by the Italian standards) should be carefully compared with the results of this method. The damage caused to the areas underlying the bridge must be considered on a case-by-case basis, since these can be extremely variable. In the case of viaducts passing through uninhabited areas, only environmental damage should be considered. Experience shows also that the interruption of crossed roads or railways is so short that the effects could be overlooked. Conversely, if the bridge overcomes urbanized areas or there are houses close to the piers, the damage will obviously be much greater and must be carefully evaluated. For this analysis, the case of Polcevera viaduct is emblematic. A document, prepared by Camera di commercio of Genoa ‡ few months after the tragedy, estimated in about a billion of euros the damages suffered by the city. In addition to the costs already mentioned, in that case nearly 600 people were displaced and some protected areas (“Red” and “yellow” zone) were created in order to isolate the zone of the disaster, so a part of the city was blocked for many months. That is why for every bridge it is necessary to examinate the area in the immediate vicinity and every construction that could be involved in the collapse. 3.4. Environmental effects

3.5. Psychological effects

To estimate the damages due to the loss of reputation, it is important to examine past events, in particular Polcevera viaduct’s tragedy. In 2017, the value of highways managed by Autostrade per l’Italia was estimated to be

‡ Università, Camera di commercio e Confindustria di Genova, Effetti economici indotti dal crollo del viadotto Morandi - stime preliminari