Research on the shear performance of hollow steel-UHPC composite bridge decks

Hollow steel-UHPC composite bridge decks offer a structurally efficient new type of system for the application of UHPC deck panels, presenting a viable solution for the lightweight construction of bridges. Nevertheless, the shear performance of composite decks and its impact on structural integrity remain to be elucidated. This study conducted shear tests and numerical simulations on hollow steel-UHPC composite bridge decks to ascertain the specific effects of shear span ratio, hollow steel tubes, and interface treatment on their failure modes and ultimate shear performance. The experimental results indicate that the shear span ratio significantly impacts the hollow steel-UHPC composite deck. As the shear span ratio decreases from 1.5 to 1.0 and 0.7, the shear strength increases by 57.3 % and 79.6 %, respectively, while the ductility coefficient decreases by 10.2 % and 52.1 %, respectively. The failure mode of the composite deck transitions from shear compression failure to diagonal compression failure. The composite performance of steel-UHPC significantly influences the shear performance of the composite deck. The shear strength of the composite deck specimens with enhanced interfaces increased by 31.8 %, and the interface slip decreased by 63.3 %. Numerical analysis revealed that the hollow steel tubes yield extensively in the shear span area, fully participating in shear resistance. Enhancing the thickness and strength of hollow steel tubes can effectively improve the ultimate load-bearing capacity of composite slabs, but has a limited effect on the initial stiffness. After interface treatment, the composite action of steel-UHPC is enhanced, and the yielding area of the steel tubes significantly increases. Finally, a formula for calculating the ultimate shear capacity of hollow steel-UHPC composite bridge decks was established, with the predicted results having an error within 10 % compared to the experimental results.