9416262 Bennett Construction with masonry infills remains very popular, particularly in the low to moderate seismic zones of the eastern/central United States. Infill walls may have both beneficial and detrimental affects on the building behavior under seismic loading. Infill walls increase the stiffness of a building, shift the structure's center of stiffness, and affect the forces in the framing possible causing premature failure of frame members. The infills can also provide a redundant load path for both horizontal and vertical loads, thus have a positive influence on the structural behavior. The objective of this project is to use data from the Northridge earthquake to characterize the beneficial and detrimental performance of infills, correlate the performance to numerical methods, and evaluate the risk associated with both unreinforced and reinforced infills. Key aspects of in-plane performance of infills that will be examined are the details of the interface between the infill and bounding frame, the alignment of the infill with the bounding frame, and the effect of the infill on the bounding frame. With respect to out-of-plane behavior, the stability of the panel and applicability of arching theories under dynamic load will be examined. This research will impact both high and moderate seismic zones. The level and priority of retrofit required for infills in high hazard zones may be less than anticipated. Perhaps just as significant is the impact on infill construction in low to moderate seismic zones, which cover most of the central/eastern Untied States. A better understanding of infills, which has to be related to actual seismic performance, is needed to take full advantage of infill construction in moderate hazard seismic zones. ***
