Résumé:
This master thesis is devoted to the fatigue design of the weld attachments and the stiffeners used in the main girders beams of an existing steel-concrete composite bridge according to the different parts of the Eurocodes dealing with the design of steel and composite bridges.
The first part of this study is primarily devoted to review the parameters that must be considered for the fatigue assessment of the structures. Both the simplified method called the λ method and the Palmgren-Miner’s cumulative damage analysis recommended by the relevant Eurocodes for the fatigue design of the structural steel, concrete and reinforcement and headed stud shear connectors were presented.
The second part of this thesis, the fatigue verification of a number of weld attachments and stiffeners is performed. The stress ranges were calculated from a global analysis for the fatigue load models FLM3 and FLM4, by modeling the composite deck with a 3D finite element model and using LUSAS 14 software.
The results obtained showed that most of the weld attachments and stiffeners do not pass the fatigue verification. It was then concluded that initially the design of the bridge did not include the fatigue verification.
