Gusset plate between bridge hanger and arch formed by a H rolled section – Design considerations based on numerical analysis

The paper investigates the detailing of the gusset plate serving as connection of the hanger to an arch member in form of a H-shaped rolled section in the frame of a tied-arch bridge. The driver of the investigation is the fatigue resistance which is usually critical for this element. Since the rolled sections used for this application belong to the same geometrical family it is possible to define a common geometric basis for this study.At first a variety of geometric shapes have been considered and analysed by means of FEM numerical simulations. This preliminary analysis has delivered a rating in term of sensitivity to fatigue resistance, with best grades obtained for the shapes with lower the stress peaks. Beside the rating based on structural performance, a second rating has been proposed based on easy of execution. The combined results from these two ratings have permitted to identify the most suitable gusset shape. This shape has been afterwards investigated more in detail in term of hot-spot stress peaks, in particular considering the influence of the different hanger – arch inclination. This study leads to a proposal for the most appropriate geometric detailing for the gusset plate in the case of the arch as H- rolled sections, providing the lowest possible stress peaks and at the same time an easier fabrication process.