PSI - Issue 19

Sandro Citarelli et al. / Procedia Structural Integrity 19 (2019) 336–345 Sandro Citarelli, Markus Feldmann / Structural Integrity Procedia 00 (2019) 000 – 000

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For such heavy loaded crane runway girders which can be assigned to the crane loading classes S3 and higher, a potential eccentric wheel load according to Eurocode 3 and Fig. 7 should be considered which further increases the local compressive stresses due to additional web bending effects.

Fig. 7. Local stresses due to centric and eccentric concentrated wheel loads

However, if the eccentricity value according to Eurocode 3 was used, the stresses would generally be too high, since in reality the eccentricities might be lower. For this reason, eccentricities were verified by strain measurements on two exemplary crane runway girders of different areas of production. They were measured via uniaxial strain gauges (SG), which should be applied on both sides of the bent web plate near the upper weld. The eccentricity can then be determined by calculating the vertical stresses resulting from the measured strains using Eq. (1), where is the distance between two transverse stiffeners and includes the shape of web plate bending. = ∙ ∙ 2 6 ∙ ∙ ∙ tanh( ) (1) where

= ( , − , ) 2 = 1 − 2 ∙ ( ∙ + )

Fig. 8. Application of strain gauges to quantify the bending component of strains within the web

As the accessibility at the upper weld area was not given from both web sides, additional strain gages were installed in correspondingly deeper but accessible areas of the web plate, which serve as additional interpolation points for the validation of the FEM model required to determine the entire stress state, see Fig. 9. In this way, mean eccentricities