Experimental Investigation on Pull-Out Test of FRP Headed Bars to Determine Bond Strength of Concrete in Exterior Beam-Column Joint

Abstract

A total of 32 pullout tests were performed for the multiple headed bars relatively deeply embedded in reinforced concrete column-like members. The objective was to determine the minimum embedment depth that was necessary to safely design exterior beam-column joints using headed bars. The variables for the experiment were embedment depth of headed bar, variation in diameter of bars. The results of the test indicated that a headed bar embedment depth of 10d_b was not sufficient to have relatively closely installed headed bars develop the pullout strength corresponding to the yield strength. All the experimental variables influenced the pullout strength. The pullout strength increased with increasing embedment depth. The purpose behind this is to study is to find bond behavior of headed reinforcement bar in concrete with variation in embedment length as well as to study bond behavior of headed reinforcement bar in concrete with variation in size of bars and shape of head. For 16 mm and 20 mm bar the result shows that the bond strength increases with respect to increase in embedment depth. Square head has maximum bond strength in comparison of Rectangular and Circular head. Circular headed bar has minimum bond strength in all specimens. There were no FRP headed bar used in the any of literatures.