Experimental study on flexural performance of steel-HFRC composite box beam

This paper will study the flexural performance of steel-hybrid fiber reinforced concrete (HFRC) composite box beams through experimental and finite element (FE) simulation analysis methods. This study aims to explore the differences in the flexural performance of composite beams under various conditions, specifically focusing on the effects of using stud and PBL ("Perfobond Leiste" in German) shear connections, the influence of normal loading (NL) and eccentric loading (EL) conditions, and the application of HFRC and normal concrete (NC). The research results indicate that under NL conditions, the failure modes of both specimens ultimately exhibited typical flexural failure characteristics and consistent with the assumption of plane section. The shear lag phenomenon of the two specimens are generally quite similar, and the overall stress level of the top rebars in the HFRC slab is significantly greater than that of the bottom rebars. However, there are certain differences in the magnitude of relative interfacial slip and the location of maximum slip between the two specimens. Compared to NL, the impact of EL on the mid-span deflection, shear lag phenomena, and rebars stress of composite beams is more significant. Under NL and EL conditions, the PBL specimen exhibited superior flexural performance compared to the Stud specimen. Furthermore, under the same conditions, the concrete slab in composite beams made of HFRC exhibits superior mechanical properties and crack resistance compared to NC.