Flexural and shear behavior of steel-UHPC composite beams: a review

Steel-Ultra-High Performance Concrete (UHPC) composite structures are a recent and innovative system with several applications. Steel-UHPC composite beams, for example, enable Accelerated Bridge Construction (ABC) due to the speed with which their components can be precast in the factory and practically installed on-site. Likewise, the improved properties of UHPC in terms of high compressive strength, ductility, toughness, and durability compared to Normal-Strength Concrete (NSC) allow for designing optimized slender cross-sections and, consequently, lower weight. Despite all the advantages offered by steel-UHPC composite beams, the study of their structural behavior began a few years ago, so there still need to be recommendations in the principal construction codes that regulate their use. In addition, review studies need to discuss the current state-of-the-art topic. This paper reviews the flexural behavior of steel-UHPC composite beams and the interaction of shear connectors at the interface through push-out tests. Two databases of push-out and flexural tests were built and discussed to address the main aspects that influence the behavior and performance of the composite system.