Abstract: “Low income unreinforced masonry structures in the southwestern region of the Western Cape Province of S outh Africa present a safety and economic threat if subjected to moderate intensity seismic activity. Previous experience and investigations conducted have shown the vulnerability to damage and/or collapse when these structures are subjected to moderate se ismicity. Most unreinforced masonry buildings in South Africa were constructed prior to the first codified provision for seismicity contained in SABS 0160 of 1989. Numerous other residential unreinforced buildings were constructed since then. To date these types of structures have not been evaluated for South African conditions, and concerns have been expressed whether these structures conform to the new codified guidelines contained in SANS 10160 - 4 of 2011, which is almost a verbatim repetition of the Euro pean code for seismic design. Before an analysis of unreinforced masonry buildings can be conducted, it is imperative to det”

Keywords: Opening size, Unreinforced masonry, Failure frequency, Failure displacement, Dynamic loading