Numerical Investigation of RC Beam Strengthened with UHPFRC Layers Using Cohesive Surface Bonding Method

Ultra high performance fiber reinforced concrete (UHPFRC) is a smart concrete material that possesses very high strength, modulus of elasticity, ductility, and excellent durability characteristics because of its very dense homogenous microstructure. Due to the excellent performance of UHPFRC, it can be used as an alternative material for strengthening and retrofitting of the partially damaged or undamaged reinforced concrete (RC) structures for restoration or augmentation of the load-bearing capacity. In the recent years, several experimental and numerical investigations have been carried out pertaining to strengthening of RC beams using UHPFRC as retrofitting layers. Most of the researchers simulated the rebars in their finite element models (FEMs) using a 2-noded linear 3D-truss element and considered the contact between steel and concrete as perfect bond. In this study, an alternative 3D finite element model was developed using ABAQUS and the bond between the rebars and concrete was modeled using cohesive surface interaction method, which was found to be a better approach for bond simulation. The results obtained using the 3D finite element models developed in this study were matched well with the experimental and numerical data obtained from the previous studies.