A new masonry building system has already been developed (5) in which a clear smoothened surface is created at plinth level and the superstructure simply rest at this level and is free to slide. In the present work the mathematical model developed for the new building system is examined for a family of earthquake with respect to the seismic force and maximum relative sliding diaplacement. It turns out from the present study that the mathematical model developed earlier (5) for the sliding system should be modified suitably to incor- porate the limitations on the maximum relative sliding displacement of the new building system.