Tensile behavior of a prefabricated Steel–UHPC composite deck system with notched perfobond strips

Abstract

This paper proposes a prefabricated steel–ultra-high-performance concrete (UHPC) composite deck (PSUCD) system equipped with notched perfobond strips (NPBLs) for long-span cable-stayed bridges. Compared with the use of an ultra-thin UHPC overlay, the proposed deck system better leverages the high compressive strength of the UHPC. Seven full-scale composite panel specimens with varying details of joint interfaces and shear connectors are subjected to tensile tests. The experimental results reveal that compared with a monolithic UHPC layer, the tensile strengths of the UHPC layer at the initial and nominal cracking (corresponding to a maximum crack width of 0.05 mm) are reduced by 47 % and 64 %, respectively, when flat joint interfaces are introduced and by 16 % and 40 %, respectively, when the interfaces are rectangular-tooth-shaped. The higher steel reinforcing ratio derived from the use of NPBLs placed across the joint interfaces leads to a distinct improvement in the post-cracking performance of the wet joints. Considering the weakened tensile strength and sectional area ratio of the joint interfaces, a prediction method for the crack widths at the wet joints in PSUCD systems is developed, and its prediction accuracy is verified.