Lateral stiffness of partially infilled reinforced concrete (RC) frames

When infill is provided in a frame up to the full height of a column fora portion it is called a fully infilled frame (FIF). Whereas, when infill is provided up to a certain height of structural frames then it is called a partially infilled frame (PIF). Partial infills are often provided in buildings for ventilation purposes. Due to the devastating collapse of buildings in the presence of partial infill as evident from past earthquakes, researchers found it important to investigate the behavior of partial infill frames in lateral loading. The present study proposes a simplified macro modeling approach for PIFs based on finite element analysis. Different PIFs were considered based on parameters such as aspect ratio, and opening area. The study also proposes a reduction factor for the effective width of the off-diagonal strut in PIFs over that of the solid reinforced concrete (RC) infilled frame to calculate its initial lateral stiffness.