Fatigue assessment of a high-speed railway composite steel-concrete bridge by the hot-spot stress method
International Journal of Structural Integrity
ISSN: 1757-9864
Article publication date: 11 June 2018
Abstract
Purpose
The purpose of this paper is to investigate the fatigue performance of a welded detail from a composite steel-concrete railway twin girder bridge caused by a passenger train circulating at varying speeds, by identifying the dynamic amplification scenarios induced by resonance. For this purpose, the hotspot stress method is used, instead of the traditional nominal stress methods.
Design/methodology/approach
This paper assesses the fatigue behavior of a welded connection considering critical stress concentration locations (hotspot). Finite element analysis (FEA) is applied, utilizing both a global and a local submodel, made compatible by displacements field interpolation. The dynamic response is obtained through the modal superposition method. Stress cycles are extracted with the rainflow counting method and the fatigue damage is calculated with Palmgren-Miner’s rule. The feasibility of five submodels with different mesh densities, i.e. 1, 2, 4, 8 and 20 mm is verified.
Findings
An increase in the fatigue damage due to the resonance effect was found for the train traveling at a speed of 225 km/h. A good agreement between the computed fatigue damage for the submodels is achieved. However, a non-monotonic hotspot stress/fatigue damage vs mesh density convergence was observed with a peak observed for the 4 mm model, which endorses the mesh sensitivity that could occur when using the surface stress extrapolation detailed rules specified in the standards for the hotspot stress method.
Originality/value
Advanced dynamic analyses are proposed to obtain local stresses in order to apply a local method for the fatigue assessment of a bridge’s structure subjected to high-speed railway traffic on the basis of the mode superposition technique resulting in much less computing times.
Keywords
Acknowledgements
The authors gratefully acknowledge the financial support for this research work provided by the Brazilian Science Foundation’s CNPq, Doctoral Scholarship No. 203662/2014-8. Authors acknowledge the Portuguese Foundation for Science and Technology for the funding, particularly through the Project POCI-01-0145-FEDER-007457-CONSTRUCT-Institute of R&D In Structures and Construction funded by FEDER funds through COMPETE2020-Programa Operacional Competitividade e Internacionalização (POCI).
Citation
Alencar, G., Ferreira, G., de Jesus, A.M.P. and Calçada, R. (2018), "Fatigue assessment of a high-speed railway composite steel-concrete bridge by the hot-spot stress method", International Journal of Structural Integrity, Vol. 9 No. 3, pp. 337-354. https://doi.org/10.1108/IJSI-11-2017-0061
Publisher
:Emerald Publishing Limited
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