Modeling the behavior of shear-dominated walls retrofitted with ultra high-performance fiber-reinforced concrete jackets

Large-scale tests of shear-dominated walls with ultra high-performance fiber-reinforced concrete (UHPFRC) jackets have shown the high effectiveness of this retrofitting solution. The jackets can suppress brittle shear failures and result in a ductile response governed by yielding of the flexural reinforcement. In addition, due to the low porosity of UHPFRC and the crack control provided by the fibers, the jackets can also provide an effective corrosion protection. However, while this retrofitting solution is very promising, there is a lack of mechanical models that can predict the effect of UHPFRC jackets. This paper proposes such a model based on a three-parameter kinematic theory (3PKT) for reinforced concrete walls. The 3PKT is extended by modeling three important effects associated with the UHPFRC jackets: tension in the fibers across the critical diagonal cracks, increased compression resistance of the critical loading zones, and enhanced crack control. The results show that the proposed approach can be used to design the properties of UHPFRC jackets in order to achieve a desired structural response in terms of strength, ductility, and crack control.