Pseudo-dynamic testing of unreinforced masonry building with flexible diaphragm and comparison with existing procedures

A full-scale one-story unreinforced brick masonry specimen having a wood diaphragm was subjected to earthquake excitations using pseudo-dynamic testing. The specimen was designed to better understand the flexible-floor/rigid-wall interaction, the impact of wall continuity at the building corners and the effect of a relatively weak diaphragm on the expected seismic behavior. The unreinforced masonry walls of this building were also repaired with fiberglass materials and re-tested. The overall building was found to be relatively resilient to earthquake excitation, even though cracking was extensive. The repair procedure was demonstrated to enhance this behavior. It was found that even though the diaphragm did not experience significant inelastic deformation, some (but not all) of the existing seismic evaluation methodologies accurately capture the rocking/sliding behavior that developed in the shear walls under large displacement. The response of the wood diaphragm and its interaction with the shear walls have also been studied. The evaluation of experimental results and the comparison with the existing procedures have revealed that the diaphragm deflections observed experimentally closely matched those predicted using the FEMA 356 and ABK models.