PSI - Issue 44

Michele Frizzarin et al. / Procedia Structural Integrity 44 (2023) 745–749

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Michele Frizzarin et al./ Structural Integrity Procedia 00 (2022) 000–000

Table 2. Left: load variation in foundation for 100% of traffic loads. Right: variation for 20% of traffic loads

L (m) Norm.33 Norm.45 Circ.52/62 DM80 DM90

L (m) Norm.33 Norm.45 Circ.52/62 DM80 DM90

10 15 20 25 30 35 40 45 50 55 60

48,21% 24,34% 13,97% 14,35% 14,64% 14,86% 15,03% 15,18% 15,30% 15,40% 15,49%

85,23% 55,41% 40,49% 31,54% 25,58% 21,32% 18,12% 15,64% 13,65% 12,02% 10,66%

41,81% 12,71% 27,98% 22,80% 10,39% 31,82% 18,24% 5,69% 22,66% 10,71% 2,62% 16,90% 5,69% 0,47% 12,94% 2,11% -1,12% 10,06% -0,58% -2,33% 7,87% -2,68% -4,17% 6,14% -4,35% -5,61% 4,74% -5,72% -6,75% 3,59% -6,86% -7,68% 2,63%

10 15 20 25 30 35 40 45 50 55 60

17,06% 8,61% 4,90% 4,81% 4,75% 4,70% 4,67% 4,64% 4,61% 4,60% 4,58%

25,97% 16,88% 12,34% 9,61% 7,79% 6,50% 5,52% 4,76% 4,16% 3,66% 3,25%

15,22% 5,32% 10,86% 8,14% 3,97% 10,84% 6,25% 2,09% 7,57% 3,67% 0,94% 5,58% 1,95% 0,16% 4,24% 0,72% -0,39% 3,28% -0,20% -0,81% 2,55% -0,92% -1,44% 1,98% -1,49% -1,94% 1,53% -1,96% -2,33% 1,15% -2,35% -2,64% 0,84%

The table highlights in red the values with increments greater than 10% for only the increase in traffic loads. 4. Conclusions In this report, a comparison between regulations relating to bridge loads has been illustrated, in order to calculate, for different deck spans, the amount of variations in foundation loads due to the regulatory update, for traffic loads only, in the hypothesis that the latter must be considered in the calculation required by § 8.4.3 of the NTC2018. This comparison is often useful in the event that the bridge deck is adapted to the traffic loads required by current legislation. This intervention can be configured as local, therefore without the need to adapt the substructures, provided that the loads in the foundation are not increased by more than 10%. It can be seen from the results of the study that if traffic loads are also considered in controlling the variation of weights, then in many cases the regulatory variation alone would lead to greater increases, especially for regulations before 1952. Furthermore, the DM90 also shows significant variations. for spans up to 30 m, due to the isolated scheme provided for by this standard. All this without considering weight increases due to structural reinforcements of the deck. From the results obtained, it can be concluded that the use of traffic loads in controlling the weight increase in the foundation would lead to the need to adapt the substructures in a very high percentage of the existing bridges in the Italian territory, both obsolete and relatively recent. References Strassil C., Romagnolo M., Ascenzi A., Burchi A., Corrado P., De Paolis F., Gigli R., Laurora A., Mandracchia L.E., Mucilli E., Rossetti A., Simone A., 2002. Linee Guida per la Revisione ed Integrazione delle Normative sulla Manutenzione e Gestione dei Ponti Stradali, XXIV Convegno Nazionale Stradale – World Road Association, Giugno 2002.

Normale N. 8 del 15/09/1933 del Ministero dei LLPP ; Normale N. 6018 del 09/06/1945 del Ministero dei LLPP; Circolare N. 820 del 15/03/1952 della Direzione Generale ANAS; Circolare N. 384 del 14/02/1962 del Ministero dei LLPP;

Decreto Ministeriale del 02/08/1980 n. 308; Decreto Ministeriale del 04/05/1990 n. 24;

Decreto Ministeriale del 14/01/2008 (Norme Tecniche per le Costruzioni NTC2008) e Circolare 02/02/2009 n. 617; Decreto Ministeriale del 17/01/2018 (Nuove Norme Tecniche per le Costruzioni NTC2018) e Circolare 21/02/2019 n. 7; Linee Guida per la classificazione e gestione del rischio, la valutazione della sicurezza ed il monitoraggio dei ponti esistenti, approvata dal CSLP il 06/05/2020.