The effect of type of mechanical anchors on bond behavior of ribbed-surface GFRP bars embedded in concrete

The deficiency in the bond between concrete and fiber-reinforced polymer (FRP) bars is a major hindrance to their widespread use in concrete structures. One effective solution to this problem is to use mechanical anchors along the bar. This research investigates the effect of mechanical anchors on the bond behavior of glass fiber-reinforced polymer (GFRP) bars embedded in concrete. In the first phase, eight beam specimens were constructed and tested in flexure , in which the FRP bars contained no anchors or anchors made of polyethylene , aluminum , or steel. The increase in maximum tensile stress in the bar was 43 %, 17 %, and 12 % for specimens with steel, aluminum, and polyethylene anchors, respectively. Steel anchors were identified as the most effective option with the greatest maximum stress and greatest initial stiffness in the stress-slip curve. In the study's second phase, an additional set of 16 beam specimens was tested to investigate the effect of the number of steel anchors. The results showed that the tensile stress developed in the GFRP bar increases at a higher rate with a greater number of steel anchors. Compared to the specimen without anchors, the bar stresses increased by 20–25 % for one and 52–59 % for two steel anchors. • The effect of different types of mechanical anchors on bond behavior of GFRP bars embedded in concrete was investigated. • Steel anchors were identified as the most effective option with the greatest maximum bond strength and initial stiffness. • The effect of number of steel anchors on bond behavior of GFRP bars embedded in concrete was evaluated. • Tensile stress developed in GFRP bar increased at a higher rate with a greater number of steel anchors. • Evidence of scratching on surface of GFRP bar and smoothing of ribs on bars over contact length with concrete was apparent.