Influence of Infill Walls on the Performance of Buildings with Different Heights

The infill wall is a supported wall that encloses the perimeter of a building and serves as partitions within the building. In the design process, infills are often disregarded due to their complex interaction with the frame, making the simulation of failure modes challenging. However, studies have shown that the presence of masonry infills cannot be neglected in structural modelling during design and verification. In the case of RC frames, infill walls can enhance global bearing capacity and also increase stiffness under lateral actions, leading to unexpected seismic performance in past earthquakes especially when they are not seismically designed. This highlights the importance of considering the contribution of infill walls in building performance under seismic forces. The aim of this study is to investigate the variation in the contribution of infill walls as the number of stories increases. Key factors such as the response reduction factor and over-strength factor are used to assess structural performance. In this study static and dynamic analyses were conducted using ETABS and SAP2000 software. The frames considered include G + 3, G + 5, G + 10, and G + 15 bare frames and fully infill frames. A parametric study was performed to evaluate variations in stiffness, response reduction factor, ductility and over-strength factor for different numbers of stories. The findings indicate that the addition of infill walls increases stiffness and base shear while decreasing ductility and maximum displacement. The fully infilled frame exhibits a higher over-strength factor compared to the bare frame, primarily due to the contribution of infills. The response reduction factor for bare frame structures increases with an increase in the number of stories from 3 to 15. Conversely, for fully infilled frames, the response reduction factor decreases as the number of stories increases from 3 to 15.