Interaction between F/TRC shear strengthening and steel stirrups: Experimental observations on real-scale RC T-beams

The increasing age, degradation, and performance demands on existing structures are driving the construction industry towards the development of high-performance materials for the production of strengthening solutions. When these solutions are used to increase the shear resistance of Reinforced Concrete elements, they tend to exhibit an adverse interaction with the stirrups. An experimental campaign was conducted to investigate this phenomenon on a rather novel material, i.e., Fibre/Textile Reinforced Concrete (F/TRC). The results of this campaign show that there is indeed an interaction which can significantly reduce the contribution of the F/TRC layers, even if the stirrups were past their yielding deformation. Furthermore, it was also observed that the reduction in contribution of the strengthening solutions was accompanied by a reduction of the deformation of the stirrups at the peak load. • F/TRC shear strengthening solutions and stirrups exhibit an adverse interaction. • The interaction between stirrups and F/TRC reduces the contribution of the latter. • F/TRC layers failed after yielding of the stirrups occurred. • The strain of the stirrups at the peak load was reduced in strengthened specimens compared to the reference one.