Bond Behavior of CFRP Bars in Simply Supported Reinforced Concrete Beam with Hanging Region

Abstract

This paper presents an experimental study on the bond behavior of longitudinal reinforcements in the hanging region (i.e., the part of the beam outside the support) of a simply supported reinforced concrete beam. Twenty-three reinforced concrete beams were tested to failure. Carbon fiber-reinforced polymer (CFRP) bars were used as longitudinal reinforcements in place of ordinary steel bars. The main test variables were (1) stirrup ratio in the hanging region; (2) stirrup ratio in the shear span; and (3) bond length in the hanging region. The test results showed that, even though the beam had a sufficient stirrup ratio in the shear span, bond-splitting failure occurred in the shear span of the beam with insufficient bond length in the hanging region. Based on the test results, the provision of ACI and AIJ codes on the additional anchorage length in the hanging region was evaluated, and a model for predicting tension force at the support was presented.