Unreinforced MASONRY system was a conventional form of construction in rural areas in worldwide countries in last decades. The main advantage of using this system is that it is cheaper than other building systems such as reinforced concrete or steel. Iranian seismic code proposes MASONRY walls confined by reinforce concrete or wooden ties. This building type called confined MASONRY is very common in Iranian construction but code provisions regarding this have not improved during recent years and are very similar to the old provisions proposed for unconfined MASONRY buildings.In this study, the specifications of confined MASONRY buildings are described. Then some equations proposed by different codes to estimate the lateral resistance of MASONRY walls are reviewed. An equation is proposed to estimate the lateral strength of confined MASONRY walls designed and built according to the Iranian codes. The proposed equation then is validated with the results of the tests the authors conducted on seven confined MASONRY walls.

MASONRY construction is the most popular and suitable for housing purposes in almost all developing countries. Base isolation in the form of pure friction is the simplest (P-F) among all isolation so far developed which can easily applied to low cost brick MASONRY buildings. The effect of the earthquake ground motion on the behaviour of isolation system is investigated analytically by using a synthetic accelerogram that is compatible with the design spectrum of IS 1893 (Part 1): 2002 corresponding to the level of maximum considered earthquake in the most severe seismic zone (PGA=0.36g). It is observed that, maximum reduction in spectral acceleration occurs with decrease in coefficient of friction at the cost of increased base sliding displacement. But for structures with Tn<0.2 sec maximum sliding displacement is 50mm for coefficient of friction 0.1. As most of MASONRY buildings are stiff structures with time period less than 0.2 second the sliding displacement are within plinth projection of 75. Hence P-F isolation is one of the best alternatives for reducing earthquake energy transmission to super structure during strong earthquake leading to lesser damages in MASONRY buildings.

According to high height and weak tensile strength of materials in minarets, it is necessary to study the structural behaviour of minarets under earthquake loading. Therefore nine historical brick MASONRY minarets in Isfahan have been modelled and analysed by applying the nonlinear finite element method for two cases: 1) the whole minaret, and 2) only the outer shell. Results show that all minarets fail due to inclined tensile cracks in bricks and bearing of materials under scaled ground motion records based on the 2800 code. Parametric study has been done to find situations in which the minarets do not undergo failure. Parameters have been the height of minarets, tensile and compressive strengths of materials, failure criterion, and damping ratio. Conventional variation of the parameters does not prevent the failure of minarets due to earthquakes.

In this research, the structural behaviour of nine historical brick MASONRY minarets in Isfahan, built in the eleventh and twelfth centuries A.D., against weight, earthquake, temperature and wind, is studied. In order to investigate the effect of the central column and spiral staircase on structural behaviour, analyses have been performed for two cases: 1) the whole minaret (including the outer shell, central column and spiral staircase), and 2) only the outer shell.Frequencies and mode shapes have been obtained by modal analysis. Seven scaled, appropriate, ground motion records have been selected, according to the Iranian Seismic Code, for non-linear time history dynamic analysis.Based on the Willam-Warnke failure criterion, all minarets fail, due to selected earthquakes. Parametric studies have been undertaken to find situations in which the minarets do not undergo failure. Parameters are the height of the minarets, the tensile and compressive strengths of materials, failure criterion, and damping ratio.By decreasing minaret height, failure is delayed or does not occur. Increase in tensile and compressive strength results in delayed failure and smaller displacement. Using the Drucker-Prager failure criterion, all minarets still fail at early stages of earthquakes. The same thing occurs by changing the damping ratio from 5% to 20%, except that the values of the displacements decrease.Structural analysis of minarets against temperature changes, according to Isfahan's thermal conditions, fire, and a dramatic decrease in temperature, shows that in cases of certain inner and outer temperature differences and very high or very low temperatures, the minarets fail. When the minaret consists of only the outer shell, it has a higher strength than the whole minaret and experiences less damage.Non-linear static analysis indicates that under Isfahan' s design wind load, (with a velocity of 130 km/h) minarets do not fail, but they will fail during winds with a velocity of 165 km/h. A minaret consisting of only the outer shell withstands larger displacements than the whole minaret.

In this paper, the behavior of MASONRY columns under working load has been studied. The effect of cracking on compression area of column or variation of moment of inertia of column along its height has been considered. The analytical solution for the critical load and deflection of the column is presented. A numerical example is presented to illustrate the method. The proposed approach has provided more realistic behavior of the MASONRY columns and proved to give an optimized critical load. The implications of the proposed study on the Indian code have also been presented.