RC Slabs Retrofitting Against Blast Loading by GFRP-PU and CFRP-PU

For reducing the structural damage against blast loading, fiber reinforced polymers sheet (CFRP, GFRP) can be used for retrofitting the RC slabs. In this study specimens of reinforced concrete slabs with or without retrofitting are modeled numerically. The results show that the using of high resistant, elastic material such as FRP sheets, are effective in reducing the deformation of the slabs, but it doesn’t significantly increase the energy absorption capacity of the structure. Using Polyurea (PU) coating with elastoplastic behavior on the FRP sheets, in addition to reduce deformation, it will increase the absorption of energy up to 40 percent. In this combination, layer arrangement is important matter, so that if the PU coating positioned on the concrete then the hard sheets are placed, its efficiency will be reduced by 30% compared the previous one. When the reinforcement element placed in front of the slab, it will increase the energy absorption up to 50 percent compared to the placing in the back of the slab. It has been shown in this study that it is not advisable to use PU alone and it should be used with stiffeners for better results.