PSI - Issue 44

Lucia Minnucci et al. / Procedia Structural Integrity 44 (2023) 729–736 Lucia Minnucci/ Structural Integrity Procedia 00 (2022) 000–000

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2.4. Decision-making process The analysis of the most probable limit state is diversified for the bridge components. The need for a component level analysis is due to the different impact that damage on certain structural elements can have not only in terms of structural response, but also for what concerns potential direct and indirect consequences. The decision making on the closure of road lanes implies the partial or total reduction of traffic flow. In this paper, four possible traffic flow reduction conditions are outlined: • Traffic Condition 1 (TC 1): closure of emergency line – no reduction of traffic flow • Traffic Condition 2 (TC 2): 50% heavy traffic flow (trucks) and 75% light traffic flow (vehicles) • Traffic Condition 3 (TC 3): 25% heavy traffic flow and 50% light traffic flow • Traffic Condition 4 (TC 4): total closure of the bridge Closure times and percentages of traffic flow can be furnished by the stakeholder, taken from the available data/literature or established basing on expert judgements. For the purpose of the preliminary applications, the decision-making process is declined in this way: • Damage (D) on superstructure  Traffic Condition 1 • Damage on substructures (D)  Traffic Condition 2 • Life Safety (LS) on substructures  Traffic Condition 3 • Life Safety (LS) on superstructure or Collapse (C)  Traffic Condition 4 As a result, an example of the evolution of the road network functionality basing on some possible recovery times is depicted in the following Fig. 3.

Fig. 3. Example of evolution of the road network functionality relating to different traffic and damage scenarios.

2.5. Quantification of traffic and environmental costs Many performance indicators can be defined to quantify the effects of the traffic alteration on the considered Origin-Destination (O-D) path; it is worth noting that each of them is associated to one of the various recovery phases of the bridge (see Fig. 3), so they result time-dependent. In this paper, preliminary results are expressed as two main indexes related to the traffic costs and the increment of pollutant emissions due to the lengthening of the travel path in presence of working zones: • TTC (Total Traffic Cost) [€] : each recovery phase is characterized by a total cost. For each j-th vehicle category, with = 1, … , , and equal to the total number of vehicle categories, , = ( � , =1 ) × (2) where =1,2 represents the free-flow condition and =2 the ongoing works condition, while , is the daily total traffic cost in each traffic flow condition for each vehicle category.