PSI - Issue 57

Jacques BERTHELLEMY et al. / Procedia Structural Integrity 57 (2024) 872–903 J. Berthellemy / Structural Integrity Procedia 00 (2023) 000 – 000

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Figure 23: Cut through a rail on a very large box girder bridge introducing a fatigue hot spot

Fig 25: Fatigue damage

Fig. 24: Mesh for the effective notch stress method

At the time of construction, stress variations under the effect of the BF truck, weighted by the traffic coefficient, did not exceed 7 MPa. However, the calculated class of the detail calculated with the method presented today is only: Calculated class = 100 . exp (0,3333 * ln(1/(2E6*0,000163))) = 14 MPa and there is no detail category in the Eurocode for such a poor detail, even in welded joints, because the hazards are then too important and the limits of Woehler's theory are exceeded. The lowest category of detail is 36 MPa. So the problem is real. Even if it is not a cause for immediate concern, it would be prudent to ensure that the project manager, who had been alerted, has had the cuts in the rails re-welded or not, and to take monitoring action if not. 4.3 Application to the fatigue evaluation of a cut for samples A very similar type of cut to that described in 4.2 is used to take a sample of the materialfor identification purposes and to determine the elastic limit. The lamellar appearance of the metal is barely visible to the naked eye. Despite the lack of protection, the plates show no signs of corrosion. What's more, I asked for a Charpy test and not a tensile test. In the case of this bridge in a rural area, the fatigue is not an issue. However, the sample taken in Figure 26 has the same very low detail class of 14 MPa. The lowest detail category is 36 MPa, which means that a less aggressive