Pullout behaviour of FRP anchors in clay bricks

Abstract

Fiber reinforced polymer (FRP) anchors have been shown to be effective for delaying or even preventing premature FRP debonding failures in concrete and masonry structures strengthened with externally bonded FRP. A number of researchers have conducted extensive research on their anchorage behaviour in concrete, but little research is concerned with the behaviour of FRP anchors embedded in masonry. An important difference between a brick unit and common concrete specimens is that the former usually has smaller dimensions. This study investigated the performance of FRP anchors embedded in solid clay bricks. Five parameters, including anchor types, hole diameter, hole depth, anchor size and brick strength, were considered in the test programme. The experimental results showed that anchors made from folded pre-wet FRP sheet has the best anchorage performance. Four failure modes were observed from the pullout tests in this study, with the brick triangular prism failure most common. The hole depth showed a more significant effect on the pullout capacity than the hole diameter. After reviewing the existing pullout strength models for concrete cone failures, two predictive and accurate pullout strength models are proposed in this paper for the triangular prism failure in bricks.