Shear Behavior of Ultra High Performance Concrete Beams without Stirrups

Ultra high performance fiber reinforced concrete (UHPC) possesses high compressive and tensile strength,as well as higher ultimate tensile strain, and this can be utilized to realize high shear capacity in UHPC beams. A finite element based numerical model is developed in ABAQUS for tracing response of UHPC beams throughout the loading range; from preloading to collapse stage. The model accounts for detailed stress strain response of UHPC in both compression and tension and strain hardening effect. Response parameters generated from the model namely deflections, crack propagation, and failure mode are alidated against measured data from experiments on UHPC beams. The developed model is applied to study the response of beams with varying shear reinforcement ratio to explore the feasibility of eliminating stirrups in UHPC beams. Results indicate that unlike conventional concrete beams, UHPC beams perform well under dominant shear loading even when no stirrups are provided. In other words, eliminating stirrups does not result in reduction of ductility and load carrying capacity of UHPC beams.