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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3.2. Infrastructure disruption

The most important parameter of this section is the duration of the restoration works after the failure of a bridge. The following table shows the number of days occurred for the reconstruction in Italian past accidents.

Table 2. Principal accident in Italy in last 10 years

Construction start date

Bridge

Cause

Collapse date

Reopening date

Flood

22/10/2013

14/11/2013

18/04/2014

Ponte Sturla di Carasco

Construction issues

07/07/2014

23/08/2015

06/03/2018

Viadotto Petrulla

Extra-heavy vehicle

28/10/2016

03/05/2018

01/07/2019

Ponte dell'Annone

Restoration issues Degradation of prestressing cables

09/03/2017

06/2018

Cavalcavia A14 n. 167

18/04/2017

2019

09/08/2019

Cavalcavia Svincolo Marene

Explosion

06/08/2018

07/08/2018

01/10/2018

Viadotto svincolo Borgo Panigale

Degradation of prestressing cables

14/08/2018

25/06/2019

04/08/2020

Viadotto Polcevera

Landslide

24/11/2019

13/12/2019

21/02/2020

Viadotto Madonna del Monte

Construction issues

08/04/2020

21/03/2021

30/04/2022

Ponte fiume Magra

Flood

03/10/2020

-

-

Ponte fiume Sesia

Flood

04/05/2023

-

-

Ponte di Longobucco

We can divide the total time frame in three parts. The first part is necessary for the activities of the judiciary, carried out to ascertain the causes of the collapse. The amount of the period could be considered as zero when the causes are quite clear (earthquake, hydrogeological accident, etc.) and equal to a little number of months when there are uncertainties. Given the dates of past accident and considering the minimum, here 6 months are proposed for traffic load failures and 0 months for all other type of accident. The other parts, that are the project and precast time and the effective building time, could be considered quite short, but they cannot be infinitely restricted because some processes, first of all the concrete maturation, cannot be shortened. Every managing company should evaluate its ability to operate within tight deadlines. In this paper we propose 1 month for the project and the empirical formula  =50log (in case of complete failure of a part of the deck), where L is the length in meters of the collapsed part, for the rebuilding time in days. For better comprehension, in the following table some results of the formula are shown.

Table 3. Durations of reconstruction

Span length [m]

Rebuilding time [days]

6

39 74

30

100

100 150

1000

Another fundamental parameter is economical loss due to missing toll payments (of course only for highways or other toll roads). It depends on the amount of traffic and of highway tolls. We could roughly estimate this cost as 2.0 euro for vehicle and for day, and we could obtain the total daily cost multiplying by the ADT value (Average Daily Traffic). Nevertheless, the right cost depends on the prices of the specific highway. Finally, it shall be considered that from the date of the collapse to the date of the reopening of the bridge, users must take an alternative route, thus taking longer to reach their destination and causing traffic to increase on other