Anchorage performance of straight rebars in UHPC with strain-hardening property

Abstract

Bond and anchorage are the basis to conduct performance analysis on reinforced-concrete structures. The strain-hardening property makes the bond-slip behaviour of rebars in ultra-high-performance concrete (UHPC) different from that in ordinary concrete. This study investigates the anchorage performance of straight rebars in UHPC based on its material properties. First, the anchorage failure process is revealed using pull-out test combined with computed tomography scanning. Thereafter, a finite element model is established to analyze the effects of strain-hardening property on failure mechanism and anchorage performance. The regularity of bond stress distribution along the rebar is also obtained. Subsequently, parametric analyses are developed to analyze the effects on bond stress, including the embedded rebar length, concrete cover thickness, and tensile strength and ductility of UHPC. Expressions for the non-uniform distribution of bond stress are established. Finally, a calculation formula is proposed for the anchorage-bearing capacity considering the strain-hardening property of UHPC material.