Carbon fiber reinforced polymers (CFRP) were widely used in strengthening of reinforced concrete members in the last few years. Experimental and theoretical investigations were carried out to find the behavior of reinforced concrete beams strengthened in shear by CFRP strips. Six beams measured of 200x300x2000mm were investigated. The variables investigated in this work are orientation (vertical and inclined) and the spacing between CFRP strips.
It was found that the strengthening by CFRP strips increased the crack, yield and ultimate load by 10%, 71% and 77% respectively on average. Inclined CFRP strips show a better performance than vertical CFRP strips with same distances and increase the yield and ultimate load by 11% and 13% respectively on average. By covering all faces of specimen with CFRP strips, the yield and ultimate load increased by 82% and 95% respectively. Using the CFRP strips changed the failure model from shear to flexural by increasing the shear strength, so the ductility was increased by 198% on average. CFRP increased the strain in compression face of concrete and the value was greater than (0.003). For all strengthened specimens, there was no effect on CFRP strips.
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