Significance of Masonry Infill Walls to Improve the Seismic Response of RC Framed Structures Through Fibre-Based Modelling

Reinforced concrete (RC) frame buildings are widely adopted for their structural integrity and versatility across the world. The behaviour of RC frame buildings during earthquakes has become a focal point of research and analysis. The most recent earthquake highlighted the crucial role of infill masonry walls in determining the extent of damage and ensuring the safety of occupants in RC buildings. To highlight the importance of this subject, the paper presents an extensive review of modelling methodologies from the last few decades, covering everything from detailed micro-model approaches to simplified equivalent diagonal strut macro-models, including technical code provisions. It also illustrates the importance of infill masonry walls in improving the seismic response of RC structures. To demonstrate this function, the study examines different 2-D models of multi-storey building frames in areas of varying seismic intensity, as classified by the most recent Indian Seismic Code. The proposed models were analysed using the software ETABS v20. In addition, the seismic performance of RC buildings was evaluated using the non-linear static pushover analysis method. After reviewing each model, the capacity of each frame to withstand seismic stress was assessed using the parameters such as period, base shear, maximum displacement, stiffness, and pushover curve. The results show that using infill walls significantly improves the shear resistance of weak column-strong beam-built RC frames, with a notable 210% improvement. In contrast, for RC frames with strong columns and weak beams, this effect is 50%. It was also observed that the open ground-floor designs are particularly vulnerable to soft storey formation, irrespective of column strength, underscoring the critical role of infill walls in reinforced concrete structural design.