MODELLING AND SEISMIC ANALYSIS OF MASONRY INFILLED R.C.C FRAMES

Abstract

In a building construction, the frame is constructed first, and then in later stages of construction, these frames are infilled by, either concrete blocks or masonry infilled bricks, or sometimes with finished stone. These masonry infilled walls provides protection from environment outside. However, in general practice the main purpose of masonry infilled walls is to fill the gap in between the building frame’s horizontal and vertical resisting elements, where it is pre-assumed that masonry infilled walls do not resist any lateral or axial loads. Hence, while designing a structure there presence is neglected, i.e. we design the structure as a bare frame only. But the main fact is that, these masonry infilled walls, to a large extent affects structural strength and stiffness properties, and on the other hand, they are very brittle in nature. Some publications like [5] contain methods for masonry infilled walls stiffness calculations and model them as equivalent diagonal pin-jointed struts. In some other references provisions have been made to consider effects of openings also. Openings in masonry infilled walls are the unescapable part, opening may be provided for windows, or doors or for some other architectural purposes. But in the presence of openings, the strength and stiffness parameters of structures which got increased earlier, start decreasing and this decrease is also dependent on the location and size of opening areas in masonry infilled walls. The aim of this study is the modelling of masonry infilled walls, using two methods, one as equivalent diagonal pin-jointed strut and another as fourznodedzquadrilateral element, using ETABS software. This study also deals with the effects of opening in masonry infilled walls in respect to their size and locations, on the stiffness parameters of structure modelled with masonry infilled walls.