Flexural capacity of steel-UHTCC (ultra-high toughness cementitious composite) bridge deck considering different shear connection degrees

Due to the excellent cracking prevention behavior of ultra-high toughness cementitious composite (UHTCC), the stud number and reinforcement ratio of composite bridge decks could be reduced, and hence the fatigue properties could be improved. In this study, a theoretical model was proposed to predict ultimate flexural capacity of steel-UHTCC composite bridge decks with different shear connection degrees. To evaluate the accuracy of the theoretical model, 10 examples were designed for finite element (FE) validation and parametric study, and the results indicated that the theoretical model can predict the ultimate flexural capacity of steel-UHTCC composite bridge decks with satisfactory accuracy. Then, quantitative analysis was conducted to reveal the effect of key design parameters on the ultimate flexural capacity. The design parameters involved in the parametric study included: (1) normalized stud number; (2) shear span length; (3) thickness of UHTCC slab; (4) reinforcement ratio; and (5) the number of longitudinal plate ribs. The reasonable range of the normalized stud number in a shear span can be determined between 0.5 and 1 in practical design and increasing of longitudinal reinforcement ratio has limited effect on ultimate flexural capacity of steel-UHTCC composite bridge decks.