Ultimate flexural capacity prediction of assembled steel-UHTCC composite bridge decks

Steel-concrete composite bridge decks (CBDs) have been widely used in practical bridge structures. In recent years, a novel assembled CBD comprising of sectional steels and perfobond rib (PBL) shear connectors was recently developed for eliminating the on-site welding requirements and reducing the steel consumption. By using ultra-high toughness cementitious composite (UHTCC) as the surface layer, the durability of the assembled CBDs could be further improved. In this paper, analytical and numerical investigations on the flexural behavior and ultimate capacity prediction of the assembled steel-UHTCC CBDs are performed. Firstly, a theoretical model considering various degrees of shear connection and the shear-slip effect of PBL shear connectors was developed to predict the ultimate flexural capacities of assembled steel-UHTCC CBDs with PBL shear connectors under both sagging and hogging moments. Subsequently, finite element (FE) models of assembled steel-UHTCC CBDs with various numbers of PBL shear connectors and profile steel parts in shapes of T, Z, B and H were established using ABAQUS, and validated against existing experimental results. Finally, the proposed theoretical model was validated using FE simulation results, with deviations not exceeding 10% and most of them are within 5%, demonstrating the accuracy of the proposed theoretical model. This paper provides a practical method to calculate flexural capacity and optimize PBL shear connector layouts, significantly improving the cost efficiency when designing CBD structure.