PSI - Issue 38

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B. Depale et al. / Procedia Structural Integrity 38 (2022) 317–330 "B. Depale-M. Bennebach" / Structural Integrity Procedia 00 (2021) 000 – 000

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Fig.2: Loading bridge number 3 (principle)

During Phase 2 (Assessment of load cases) it was necessary to update the first set of load combinations, notably because the design loading references (old national standards) were obsolete and because the real traffic was greater than the design assumptions, notably due an increase of the maximal load per lorry (44 tons instead of 38 tons) and because many East-European lorries are overweighted. In order to establish the real loading distribution of bridge and corresponding load spectra of portal structure, a campaign of measurement of the real traffic (types of cars, buses, lorries and their distribution) was launched for several weeks for all the bridges. For the bridge number 3 under consideration, the number of cycles of the period 2006-2020 was also extrapolated from the most severe five years of the period 1980-2005 and the fatigue load combination retained was conservatively the most critical distribution of vehicles (with three lorries) observed during this campaign. Finite Element Analyses (FEA) have been performed during Phase 3.1 (Global calculations) for both bridge and portal structure, based on refined models made of plate elements, and all stress concentration areas have been identified (see Figure 3).

Fig. 3: A typical map of von Mises stresses, in the bridge, and in the portal structure