Document Type : Research Paper


1 Civil Engineering Department, Collage of Engineering, University of Mosul

2 Departement of Civil Engineering, Collage of Engineering, University of Mosul


The use of external strengthening by fiber reinforced polymer (FRP) technology has significantly increased in recent decades. This is because (FRP) has the properties that make it the most suitable option for strengthening and rehabilitation of damaged concrete structures instead of using traditional materials such as steel plates. In this paper, the behaviour of non-reinforced concrete beams externally wrapped with Glass Fiber Reinforced Polymer (GFRP) sheets has been examined. Fourteen unreinforced concrete prisms were cast with a rectangular section of (150 × 125 mm) and a length of (760mm), these specimens were divided into five group. First group was not externally wrapped with GFRP sheets (control specimens), and the remaining groups were GFRP wrapped with a variable number of GFRP layers (thickness of wrapping). In the first stage of study, the prisms have been tested and the effect of external wrapping and increasing the wrapping thickness on the behaviour of prisms was observed. In the second stage, the unwrapped concrete prisms that were tested and failed (control specimens) were rehabilitated by externally wrapping them with one layer of GFRP sheets. The results have shown that wrapping with GFRP sheets increased the capacity of the prisms and failure load had reached to (342.5%) for prisms wrapped with three layers when compared to the control specimens. It was also noticed that there was an increase in the toughness of the prisms by increasing the number of GFRP layers. The results have shown that there was a decrease in the failure load of the four layer wrapped prisms, and this was due to the early failure of the prisms due to the debonding of the GFRP sheets from the prism surface. The damaged specimens which were later rehabilitated have shown an increase in load carrying capacity compared to the control specimen.