This study evaluates the seismic performance of reinforced concrete (RC) frame structures with different infill materials using analytical modeling techniques. Five types of infill- common brunt clay bricks, AAC blocks, gypsum board, lime-based solid blocks, hollow concrete blocks -were considered to assess their impact on key seismic response parameters such as base shear, displacement, time period, and minimum beam-column sizes. Finite element modeling was performed using ETABS v20, with infills idealized as equivalent diagonal struts based on their material properties and stiffness characteristics. Response spectrum analysis were employed to simulate structural behavior under seismic loading. Results show that brick-infilled frames and concrete blocks exhibit higher stiffness but also higher seismic mass, resulting in increased base shear and structural member sizes. AAC blocks significantly reduce base shear and fundamental time period due to their light weight, though they lead to increased lateral displacement. Lime-based solid blocks demonstrated a balanced performance, offering reduced seismic demand, moderate stiffness, and controlled displacements while maintaining sustainable construction benefits. The overall analysis demonstrates that the lighter infill materials like AAC and gypsum reduce base shear, they may permit excessive lateral deformation. Conversely, denser materials improve lateral stiffness but increase seismic demand. Therefore, in earthquake-prone regions like Nepal, where both seismic safety and cost-efficiency are vital, the infill wall material must be selected based on a balance between displacement control and seismic force minimization. Further research is recommended in areas such as effects on asymmetrical buildings, experimental validation, non-linear interaction modeling, and the development of hybrid infill systems for optimized structural and environmental outcomes.
Ojha et al. (Fri,) studied this question.