Performance of Postinstalled GFRP Bars in Structural Connections

This research experimentally investigated the applicability of glass fiber-reinforced polymer (GFRP) bars as postinstalled reinforcement in structural connections. The test specimens included two identical vertical elements, which were anchored into a reinforced concrete base using postinstalled GFRP bars replicating a beam-column or beam-wall connection. The variables investigated included the GFRP bar embedment depth (150 and 290 mm), concrete compressive strength (20.7 and 41.4 MPa), and postinstalled GFRP bar size (Nos. 13, 19, or 25). A total of 16 specimens were subjected to combined tension and shear loading. Concrete breakout in tension was the failure mode in all specimens. The concrete breakout strengths improved by increasing the embedment depths and concrete strengths and worsened as the GFRP bar diameter increased while keeping the embedment depth and concrete strength constant. The authors recommend using anchor provisions from current standards to estimate the concrete breakout strength of post-installed GFRP bars (Nos. 13-19) tested with the parameters described herein.