Fatigue Assessment of Welded Connections in I-Girder Composite High-Speed Railway Bridges

The determination of the dynamic performance of a high-speed (HS) railway bridge is an ever-increasingly topical matter in public transportation networks owing to the broad establishment of ongoing HS railway transportation networks and the implementation of conventional networks for superior operational vehicle velocities. This paper examines the fatigue performance of a welded gusset plate connection of a composite steel I-girder railway bridge under trains moving within a certain range of velocities. The global three-dimensional finite element models (FEMs) are applied to examine the dynamic response of the I-girder composite steel-concrete railway bridge. The natural frequencies of the numerical model of bridge are verified using ambient vibration test results. A local three-dimensional FEM is generated in accordance with critical welded gusset plate connection using the ABAQUS platform. The local submodel is generated congruent with displacement field interpolation. The fatigue performance of a welded joint zone considering critical stress accumulation regions is determined by the hot-spot stress method under resonance conditions due to train passage with varying velocities. Stress cycles are extracted by taking real traffic spectra into account. Fatigue damage is calculated by using Palmgren-Miner’s rule and the rain-flow counting method. The outcomes demonstrate that the bridge is not vulnerable to the forthcoming fatigue failure mode.