Retrofitting URM cavity walls for out-of-plane composite behaviour

Experimental research has been performed previously to measure the out-of-plane (OOP) seis-mic performance of in-situ and retrofitted unreinforced clay brick masonry (URM) walls with solid thickness-es of contiguous and overlapped masonry leaves. However, comparatively little experimental research has been performed on URM walls with cavities (such as continuous air gaps separating leaves of brick from one another), despite the prominence of cavity masonry construction in various parts of the world. Hence, re-search was pursued with an emphasis on efficiently retrofitting URM cavity walls to enable the formation of composite behaviour when subjected to simulated seismic OOP loading consisting of both quasi-static load-ing of existing wall panels using airbags and dynamic loading of laboratory specimens using a shake table. Eleven tests were performed on URM cavity wall panels. The intended outcomes of the research reported herein included measuring the improvement of strength and displacement capacities of URM cavity walls due to retrofit improvements in which separated cavity wall leaves were connected together using various types, quantities, and spacings of ties; comparing the difference in measured capacities and cracking behaviour be-tween quasi-static airbag testing and dynamic shake table testing; establishing an equivalent solid wall thick-ness for retrofitted cavity walls for use in existing OOP predictive models; and developing a provisional pre-dictive model for estimating the capacity of URM cavity walls retrofitted to behave semi-compositely or fully compositely.