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 interve...

The progressive damage and subsequent demolition of unreinforced masonry (URM) buildings arising from the Canterbury earthquake sequence is reported. A dataset was compiled of all URM buildings located within the Christchurch CBD, including information on location, building characteristics, and damage levels after each major earthquake in this sequence. A general description of the overall damage and the hazard to both building occupants and to nearby pedestrians due to debris falling from URM buildings is presented with several case study buildings used to describe the accumulation of damage over the earthquake sequence. The benefit of seismic improvement techniques that had been installed to URM buildings is shown by the reduced damage ratios reported for increased levels of retrofit. Demolition statistics for URM buildings in the Christchurch CBD are also reported and discussed.

This paper presents test results of ten single-story reinforced concrete masonry shear walls. Test results are summarized and compared with design formulae specified by the New Zealand masonry design standard NZS 4230:1990 and by the National Earthquake Hazards Reduction Program. It was determined that the test walls exhibited shear strength significantly exceeding the NZS 4230:1990 maximum permissible shear stress, confirming that NZS 4230:1990 was overly conservative in accounting for masonry shear strength. It was also confirmed from the test results that masonry shear strength increases with the magnitude of applied axial compressive stress and the amount of shear reinforcement, but that the shear strength decreases inversely in relation to an increase in wall aspect ratio. In addition, it was shown that the postcracking performance of shear dominated walls was substantially improved when uniformly distributing the shear reinforcement up the height of the walls.