Research on Design Method of FRP Anchor in RC Columns Confined with Bidirectional FRP Sheets

In retrofitting the existing reinforced concrete (RC) frame structures, the improvement of seismic grade leads to the composite strengthening demands of columns. The bidirectional fibers reinforced polymers (FRP) sheets can be tensioned in two ways, and subsequently, the shear and flexural capacities of confined columns are simultaneously improved. In this article, the bidirectional FRP sheets with fiber anchors were designed and applied, and three specimens were tested under low cyclic lateral loading. The test results showed that the failure mode of the RC column changed after strengthening, the effective strain of longitudinal fibers in FRP sheets significantly increased when using fiber anchor, and the flexural capacity of the column was further improved.