PSI - Issue 57

Elena Sidorov et al. / Procedia Structural Integrity 57 (2024) 316–326 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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into account for these welds in fatigue design. In summary, continuous and intermittent rail welds demand for different nominal stress calculations. In the fatigue design, stress ranges have to be derived from the nominal stress history that are finally compared with an appropriate detail category in the check against fatigue as shown in Figure 2. The stress-raising effects caused by the weld geometry (notch effect) and by the material(residual stresses etc.) shall be taken into account by the fatigue strength of the detail category within the nominal stress method. The present version of EN 1993-6 (2007) and EN 1993-1-9 (2005) provide neither a sufficient nominal stress definition nor a proper detail category for rail welds. Therefore, the paper is reviewing recently finalized research on both aspects. In particular, the paper is presenting an investigation on the decisive influences for the nominal stresses in intermittent rail welds. Thus, the main focus of the paper is laid on the determination of the action effect within the fatigue verification procedure of rail welds as shown in Figure 2.

Fig. 2. Principal approach for thefatigue verification ofrail welds subject to transverse normal stresses caused by wheel loads (simplified)

Nomenclature a

weld size rail width wheel load

b r F

spacing of intermittent rail welds

g

gap size

g con

weld length rail height

h

h r

length of crane runway beam effective loaded length

L

eff

p maximum vertical force in both welds per unit length [N/mm] ; called ‘weld pressure’ in the paper  nom nominal stress in the rail welds caused by wheel load introduction [N/mm²]

2. State of the Art The design rules for the fatigue check of crane runway beams including rail welds are given in EN 1993-6 (2007). Up to now, there have been no rules for calculating the nominal stresses in rail welds caused by wheel loads. The nominal stress in the rail welds is influenced by the contact between the rail and the flange that controls the proportion of the wheel load that is carried by the rail welds.