Abstract—South Africa has some regions which are susceptible to moderate seismic activity. A peak ground acceleration of between 0.1g and 0.15g can be expected in the southern parts of the Western Cape. Unreinforced Masonry (URM) is commonly used as a construction material for 2 to 5 storey buildings in underprivileged areas in and around Cape Town. URM is typically regarded as the material most vulnerable to damage when subjected to earthquake excitation. In this study, a three-storey URM building was analysed by applying seven earthquake time-histories, which can be expected to occur in South Africa using a finite element approach. Experimental data was used to calibrate the in- and out-of-plane stiffness of the URM. The results indicated that tensile cracking of the in-plane piers was the dominant failure mode. It is concluded that URM buildings of this type are at risk of failure especially if sufficient ductility is not provided. The results also showed that connection failure must be investigated further. Keywords—URM, Seismic Analysis, FEM. I. INTRODUCTION ARTHQUAKES are very common natural hazards, which, depending on its magnitude could lead to catastrophic disasters. Countries such as Haiti, New Zealand, Japan, for examples, have recently experienced catastrophic damage caused by earthquakes, resulting in billions of dollars of damage and significant loss of human life. Table I shows a list of earthquakes which caused the greatest number of fatalities since 2000 [1]. Based on this data it is evident that moderate intensity earthquakes, such as the Haiti earthquake, can result in catastrophic calamities with respect fatalities and its overall effect on the country’s economy. We notice that in the case of Haiti, which experienced a moderate intensity earthquake, the estimated damage was more the double the country’s annual GDP. A natural disaster of this magnitude obviously has a devastating effect on the country’s economy. The degree of damage the building can sustain is a function of many aspects but can mainly be attributed to the magnitude of the earthquake as well as the design and construction standards. Countries that do not have or have ineffective seismic provisions in their relevant building codes of practice are more at risk of sustaining major damage and even collapse of civil engineering infrastructure. Therefore, it is important for countries that are at risk of moderate to severe seismic activity require a robust seismic code of practice to ensure that its civil engineering infrastructure can resist the effects of earthquake loading. T. N. Haas is with the Department if Civil Engineering, Stellenbosch University, Private bag X1, 7602, Matieland, Stellenbosch, South Africa (e- mail: trevor@sun.ac.za). T.van der Kolf completed his Masters’ degree thesis in December 2013. He is working as a structural design engineer at Uhambiso Consult in Port Elizabeth, South Africa (e-mail: tvanderkolf@uhambiso.co.za). South Africa can be considered seismically stable based on the seismic hazard map [5]. This map indicates that the majority of the country could be exposed to a maximum peak ground acceleration (MPGA) of 0.05g with a 10% probability of being exceeded in 50 years. In addition the general public and government officials do not perceive earthquakes as a major threat due to its scarcity. This however raises a false sense of comfort as the same seismic map also shows certain regions in the Western Cape Province of South Africa to be susceptible to a MPGA of 0.15g. The same region is at risk to a much greater MPGA of 0.20g to 0.27g [6]. Therefore, this region is susceptible of experiencing moderate to strong PGA’s, which has the ability to cause significant damage to civil engineering infrastructure which are poorly designed / not designed for seismic excitation. TABLE I MOST DESTRUCTIVE EARTHQUAKE IN TERMS OF FATALITIES SINCE 2000 Country Richter Magnitude [2] Fatalities [2] Estimated damaged caused [3] Estimated GDP at time of earthquake [4] Haiti 7.0 316 000 $ 14 Bil $ 6.5 Bil Sumatra 9.1 227 898 $ 4.5 Bil $ 256 Bil China 7.9 87 587 $ 150 Bil $ 4 522 Bil Pakistan 7.6 80 361 $ 5.2 Bil $ 110 Bil Iran 7.4 50 000 $ 7.2 Bil $ 116 Bil Iran 6.6 31 000 $ 1.9 Bil $ 135 Bil Japan 9.0 20 896 $ 309.0 Bil $ 5 897 Bil India 7.7 20 023 $ 5.5 Bil $ 494 Bil Previous international research work shows that URM is a brittle material with low tensile strength and limited post cracking deformation capacity [7]. Masonry exhibits a non- homogeneous behaviour due to the distinct material properties of bricks and mortar as well as the complex material interactions. Experimental tests show that the properties of the masonry material are not a linear combination of the clay bricks and mortar’s material properties [8]. Different mortar strengths and brick strengths as well as construction quality and material workability cause the masonry properties to vary significantly; [9]-[12]. Therefore, the uncertainties regarding masonry’s material properties make the evaluation of the seismic performance of URM building extremely difficult. URM buildings require a sound conceptual design to account for the many uncertainties associated with URM and seismic loads [7]. Research also shows that URM structures performed poorly during past earthquakes of low to moderate seismicity and is also considered the most vulnerable construction material when subjected to seismicity, [7], [13]. URM structures are therefore not recommended for construction in Trevor N. Haas, Thomas van der Kolf Seismic Analysis of URM Buildings in S. Africa E World Academy of Science, Engineering and Technology International Journal of Civil and Environmental Engineering Vol:8, No:12, 2014 1267 International Scholarly and Scientific Research & Innovation 8(12) 2014 scholar.waset.org/1307-6892/9999942 International Science Index, Civil and Environmental Engineering Vol:8, No:12, 2014 waset.org/Publication/9999942