Bond Behavior of Near-Surface Mounted FRP Bars to Masonry

Abstract

The contribution of near-surface mounted (NSM) fiber-reinforced polymer (FRP) bars to the shear strength of unreinforced masonry (URM) walls built with concrete masonry units (CMU) was evaluated, and results are presented in this paper. This evaluation was achieved by reviewing test results from three types of research programs that were previously reported in the literature. Experiments were grouped as follows: (1) pull-out tests of NSM FRP bars embedded in CMUs, (2) pull-out tests of NSM FRP strips in clay brick prisms, and (3) in-plane diagonal compression tests of URM walls strengthened with NSM FRP bars/strips. Experimental results clearly indicate a significant difference in the failure mode observed between pull-out and in-plane diagonal tests, and statistically the maximum strains registered in NSM FRP bars/strips were significantly higher in pull-out type tests. Results from the pull-out tests were subsequently used to develop a bond stress–slip model for NSM FRP bars embedded in concrete masonry. Finally, the contribution of NSM FRP bars to the shear strength of concrete URM walls derived from different approaches is presented in this paper.