FE simulation of FRP-from-masonry delamination: three-dimensionaleffects and interface traction assessment

Delamination of FRP-reinforced masonry is a complex phenomenon, which, in principle, may involve both the adhesive joint and the masonry. When recourse in made to highly resistant adhesives of recent conceiving, the quasi-brittle response of the heterogeneous support is expected to play the major role. At a structural level, delamination response can be described effectively also by concentrating all the sources of dissipation and non-linearity at the masonry-FRP interface, and by assuming the support to behave linearly elastically. In this paper, a detailed and critical comparison between two different fully three-dimensional Finite Element models is developed: a first model in which only the masonry is damageable whilst the FRP reinforcement adheres perfectly to the support, whereas in the second model a zero-thickness, cohesive interface is located between the FRP and the support, whilst masonry behaves as a linear elastic material. The overall response during delamination and local traction distributions at the interface are critically investigated, varying the FRP reinforcement width.