Abstract Summary
ABSTRACT Nowadays, transport policy is decisively influenced by environmental concerns, with railways expected to play a key role in achieving climate neutrality by 2050, according to the Green Deal proposed by the European Commission. The increase in railway traffic will require the expansion of the network, which must be done in part by kepping in service existing bridges as long as possible. Among the major threats to the structural integrity of these infrastrutures, fatigue is particularly relevant and may lead to local or global collapse. The codes in force propose global methods based on S-N curves for nominal stresses to assess fatigue damage. Nevertheless, this calculation philosophy leads to relevant and conservative approximations between the geometrical and material characteristics of a given existing detail and those that define a certain relatable normative S-N curve. The implementation of local fatigue approaches based on submodelling leveraged by modal superposition principles is critical to overcome these limitations, allowing the analysis of the local response of the real load transfer mechanism. This type of calculations can be assumed as an advanced stage applied to critical details identified using the mentioned normative global methods, following a multiphase strategy from global to local scale. In this context, an integrated methodology for fatigue life prediction of existing metallic railway bridges is suggested and applied to a real case study demonstrate the added value. Acknowledgments This work was financially supported by: Base Funding - UIDB/04708/2020 of the CONSTRUCT - Institute of R&D In Structures and Construction - funded by national funds through the FCT/MCTES (PIDDAC) and carried out within project IN2TRACK3 [101012456-H2020-S2RJU-CFM-2020]. Keywords: railway bridges; fatigue assessment; local fatigue approaches; submodelling relations; modal superposition.
