The analysis of efficiency of GFRP and CFRP covers to reinforce concrete beams under various conditions

Abstract

Application of Fibre Reinforced Plastic (FRP) composites has been very widely developed for seismic reclamation during recent years. One of the important reasons that may be implied for selection of these materials is the high tensile strength, low-weight, and also flexibility of the system in these materials and very high durability of them. Rather than describing of installation technique of recent studies, it has been dealt with bending-shear behavior in the reinforced concrete beams with Glass-Fibre Reinforced Plastic (GFRP) and Carbon Fibre Reinforced Plastic (CFRP) composites. For this purpose, the concrete reinforced beams have been analyzed by various techniques and using built-in glass and carbon fibers. The carbon-fiber built samples without the end brace and other samples with end-brace were anchored by glass fibers. Similarly, glass-fiber reinforced plastic (GFRP) beams were built with and without bracing at end and reserved under laboratory conditions. These fibers have been installed in tensile point of beams and by means of epoxy adhesive and also one sample was built as control beam without using fibre. On the other hand, some solid and hollow beams were prepared as well. The results of experiments indicate that rates of rising strength for non-bracing carbon and glass were about 19-40% and 8-43% respectively and the strength were increased for braced carbon and glass 17-75% and 10-82% respectively. In hollow cylindrical column enclosed the compressional strength has increased 66% in one CFRP layer, 96% in two CFRP layers, and 123% in three CFRP layers while application of GFRP has increased compressional strength up to 36% in one GFRP layer, 63% in two GFRP layers, and 105% in three GFRP layers for hollow cylindrical column. In solid cylindrical enclosed by one CFRP layer the compressional strength has increased 71%, 138% in two CFRP layers, and 154% in three CFRP layers while application of one GFRP layer has increased compressional strength 45% and in two layer GFRP layer 79% and in three GFRP layers it has been increased up to 144% for solid cylindrical column. The rate of increase in final resistance at beams reinforced by bending-shear strength is greater than final resistance in other beams.