Experimental Investigation on the Behavior of RC Beams Strengthened by Externally Placed BFRP Sheets

Abstract

The concept of using fibers to improve the various properties and characteristics of the concrete is very old. From the last two decades, the use of Fiber Reinforced Polymer (FRP) in civil and structural engineering is going on very large scale. Many researchers or sc holars have conducted various experiments for the investigation of behavior of strengthening of beams with FRP for increasing the load carrying capacity in shear as well as in flexure. All new types of innovations of structural engineering are developing by using FRP composites. These innovations depend upon various parameters like the type of fiber using, the arrangement of placing of fiber, the pattern of loading, the type of composite materials and also on the bond behavior between FRP and concrete. The focus of this research work is to study the behavior of externally placed Basalt Fiber Reinforced Polymer (BFRP) on the load carrying capacity of the RC beams. In the study, R C beams were casted as under-reinforcement beams and strengthened by providing BFRP strips in different orientation such as rectangular strips of BFRP, inclined strips of BFRP and fully U-wrap of BFRP and the effect of the same of behavior of beams were studied. For the validation of the experiment results, theoretical calculations were also made by using various analytical methods as mentioned in literature. All the beams are of length 2050mm , width 135mm and of 270mm depth and provided with a reinforced of 2-12 mm bars in tension zone and 2-10 mm bars in compression zone. Tests were performed by using four point loading technique and for measuring the displacement, LVDT was placed at mid-point of the beam. After conducting the test, the results shows that the strengthen procedure by using BFRP sheet increase the first crack load by 10% to 46% and the ultimate load carrying capacity of the beams increased up to 36%. The stiffness of the beam strengthened with inclined strips was highest among all the beams. And the results of the analytical studies justified that the results obtained in experiment studies are correct and failure of the beams was according to the expectation.