Assessment of performance criteria of reinforced concrete beams retrofitted with FRP fabrics subjected to extreme impulsive loading

The study performed in this paper is limited to the reinforced concrete structures, in which the behavior of reinforced concrete beams retrofitted with FRP fabrics subjected to extreme loading is investigated. In this regard, numerical modeling using finite element software LS-DYNA is carried out. Numerical results are validated against the results of laboratory experiments. Strengthening of beams with an external composite layer of carbon, glass and Kevlar fibers are considered. Common performance criteria of concrete members such as deflection ratio, support rotation, and ductility ratio as well as crack pattern and energy absorption are investigated. Results show full wrapping mode with carbon fibers leads to the most reductions in the growth of flexural cracks as well as flexural-shear cracks along the free span of the beam. The ductility of the beam is reduced in different states of retrofitting, which the greatest amount of ductility reduction is obtained when reinforced with carbon fibers. Elastic and plastic energies absorbed by the retrofitted beam are, respectively, increased and decreased in all of the investigated cases. Retrofitting with carbon fibers in different states shows the largest increase in the absorption of elastic energy and also the greatest reduction in the plastic energy absorption.