Numerical study on the effects of stud degradation and stud arrangement on the fatigue performance of steel-UHPC composite decks

The fatigue degradation of stud connectors is generally neglected in the fatigue analysis of steel-UHPC composite decks, which may lead to inaccurate results. This paper studies the effects of stud degradation and stud arrangement on the fatigue behavior of steel-UHPC composite decks via finite element analysis. A numerical method for the fatigue analysis of composite decks is proposed considering the fatigue degradation of studs. The numerical method is experimentally validated and applied to evaluate the fatigue performance of composite decks. The effect of stud arrangement on the fatigue response of composite decks is studied by parametric analysis. The results indicated the fatigue degradation of studs and the decrease in stud spacing caused more uniform distribution of shear forces at steel-UHPC interfaces. The fatigue degradation of stud connectors reduced the structural stiffness, while reducing the stud spacing enhanced the local stiffness but increased the stress ranges of some fatigue-critical details. Neglecting the stud degradation could lead to an underestimation of the fatigue life of stud connectors. This study advances the understanding of the fatigue behavior and the ability to analyze the fatigue behavior of steel-UHPC composite decks.