Diagonal Compression Testing of FRP-Retrofitted Unreinforced Clay Brick Masonry Wallettes

Abstract

To address concerns regarding the seismic vulnerability of New Zealand unreinforced masonry (URM) buildings, a research program was undertaken to investigate the effectiveness of fiber-reinforced polymer (FRP) systems as a seismic retrofit intervention for in-plane loaded URM walls that are prone to fail in a shear mode during earthquakes. Seventeen URM wallettes were retrofitted with either externally bonded (EB) glass FRP fabrics, EB pultruded carbon FRP (CFRP) plates, or near-surface mounted pultruded CFRP rectangular bars. The wallettes were tested by the application of a diagonal compressive force, and data were recorded for applied force and corresponding wall drift. Results were compared with five nominally identical unretrofitted wallettes. It was determined that the FRP systems substantially increased the shear strength of the wallettes. Significant increases in the pseudoductility and the toughness were also obtained, which are all considered to be important goals of any seismic retrofit intervention.