Static Analysis of Masonry Infilled R.C.Frame With &Without Opening Including Soft Storey of Symmetric Building

Abstract

Masonry infill is considered as a non-structural element in all type of buildings where masonry use. But, masonry infill walls are mainly used to increase initial stiffness and strength of reinforced concrete (RC) frame buildings. This Open First storey is also termed as Soft Storey. The upper storeys have brick infilled wall panels with various opening percentage in it. In many cities of India, it is very common to leave the first storey of masonry infilled reinforcement concrete (RC) frame building open preliminary to generate parking space or any other usage in the first storey. Such buildings are highly undesirable in seismically active areas. In the present study, it is an attempt to access the performance of masonry infilled reinforced concrete (RC) frames with soft storey of with and without opening. In this paper, symmetrical frame of college building (G+5) located in seismic zone-III is considered by modelling of initial frame. According to FEMA-273, & ATC-40 which contain the provisions of calculation of stiffness of infilled frames by modelling infill asEquivalent Diagonal Strut Method. Therefore, the infill panels are modelled as equivalent diagonal strut method. The error involved in modelling such buildings as neglecting the presence of infills in the upper storeys, is brought out through the study of an example building with different analytical models. This linear static analysis is to be carried out on the models such as Strut frame with 15%, 20%, & 25% centre &corner opening, which is performed by using computer software STAAD-Pro from which different parameters are computed. In which it shows that how infill panels increase the stiffness of the structure. While the increase in the opening percentage leads to a decrease on the lateral stiffness of infilled frame. This paper highlights the importance of the presence of the open first storey in the analysis of the building.