non linear analysis with ABAQUS

Dear Abaqus Users,

I have modelled and analysed a simply supported RC Slab strengthened with FRP using ABAQUS 6.8-2. Plastic analysis with Concrete Damaged Plasticity has been chosen to simulate the behavior of the RC Slab loaded at the centre. However, I have difficulties about the constraints between the surface of FRP and surface of the RC Slab. Abaqus did not recognise "tie" element for this interface between these materials. A good comparison between this simulation and the experimental test result is expected. However, tie constraints made the analysis to be terminated.