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.

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.

This paper describes the impact of the 4th September 2010 and the 22nd February 2011 Canterbury earthquakes on MASONRY buildings.Christchurch and the surrounding areas have more than a thousand old buildings built of unreinforced brick and stone MASONRY. Several unreinforced MASONRY (URM) buildings were damaged (some very severely) in the September earthquake; whereas the February earthquake caused severe damage (many collapsed) to most URM buildings in Christchurch; requiring them to be demolished. As expected, retrofitted URM buildings generally performed better, but in the February earthquake several retrofitted buildings were also severely damaged. URM buildings with perimeter walls partially anchored using small and sporadic anchor bolts not extending to the full perimeter and height of the walls suffered severe damage. On the other hand, URM buildings that were systematically retrofitted to avoid the perimeter walls from detaching from each other and from the floor and roof sustained the severe shakings of the February earthquake with only minor damage.