Numerical simulation of bond-slip interface and tension stiffening in GFRP RC tensile elements

Bond between reinforcement and concrete highly affects the structural behaviour of reinforced concrete (RC). Introduction of bond-slip models into numerical simulation allows taking into account the bond interaction and analyse its effect on local and global behaviour. Unlike conventional steel reinforcement, no standard bond-slip law exists for FRP reinforcement, as bond is the result of a combination of parameters such as reinforcing material and bar surface configuration, among others. Therefore, there is a need in developing a methodology to easily implement bond-slip response from experimental bond tests. In this work, a methodology to implement bond-slip behaviour between concrete and reinforcement into a FEM model is presented. The inverse analysis is used to characterise the bond mechanisms active in a pull-out test. The obtained constitutive behaviours are thereafter implemented into a FE program by using connector elements and surface-to-surface contacts, and GFRP RC tensile elements are modelled. Numerical results are compared to experimental ones available in the literature, showing good accuracy in terms of load-deformation, crack width and crack spacing, as well as strains and bond stress and slip distributions along the reinforcing barThe authors acknowledge the support provided by the Spanish Government (Ministerio de Economía y Competitividad), Project. BIA2013-46944-C2-2-