Analytical and Numerical Study of FRP Retro tted RC Beams Under Low Velocity Impact


1 Department of Civil Engineering,Sharif University of Technology

2 Department of Civil Engineering,Amirkabir University of Technology


Abstract. An analytical along with numerical analysis has been carried out to investigate the behavior
of concrete simply supported beams strengthened with Fiber-Reinforced Polymer (FRP) unidirectional
laminates under impact loading. Concrete beams are reinforced with a minimum ratio of
exural and
shear steel rebars and nally retro tted with epoxy-bonded high strength carbon FRP laminates in their

exure surfaces. The impact force was applied with a solid steel cylinder drop weight. Analytical results
showed that composite laminates externally bonded to reinforced concrete beam substrate can signi cantly
enhance the performance of theses structural members to resist impact loadings. Also, based on the
obtained results, in retro tted beams the crack propagation happens in a desirable mode; an increasing
of yielded rebar zones and residual beam sti ness. Retro tted beams were sti er than unretro tted ones
in their rst impact response. The residual sti ness of impacted concrete beams depends on their initial
sti ness and the impact energy level. The analytical method uses an idealized elastic spring-mass model
exural wave propagation theory to calculate the dynamic response of assumed beams. Analytical
responses are adjusted due to an inelastic response, and nally are used for the simpli ed designation of
impact resisting reinforced concrete beams retro tting laminates.