Effect of masonry infill for reducing the sway of RC frame using finite element modeling

Sway of reinforced concrete (RC) frame subjected to lateral load is an important design parameter from serviceability point of view. In Bangladesh, brick infills are used as exterior walls and partitions. Present code of practice does not include provision of taking into consideration the structural effect of infill in multi-storeyed building construction. Yet, the presence of infill increases the lateral stiffness of the structure and reduces the value of sway. For this, if it is taken into consideration, the resulting structure will be economic. Thus, there is a scope of investigation on the importance of infill in a frame structure. In this paper, an investigation based on finite element modeling of reinforced concrete frame in the presence of masonry infill subjected to lateral loads is carried out to study the sway behavior of RC frame. The frame is modeled as a two-dimensional structure using two dimensional frame elements to model beam and columns, and the in-plane stiffness of brick wall, contributing to stiffness of the frame against lateral load, is modeled by a spring damper element. Lateral loads (seismic load) are calculated as described in Bangladesh National Building Code, 1993. Here, a ten storey and four bay building frames are taken as reference structure and an extensive investigation is performed under various parametric conditions to determine the deflection characteristics of RC frames with infill. It is hoped that this work will enable designers to capitalize on the effectiveness of using finite element modeling in reducing sway of building frame.