Seismic performance and fragility assessment of masonry infilled RC frames using a numerical approach

Damage to masonry infill walls can result in substantial property loss and pose a serious risk to human safety. The behaviour of masonry walls under seismic load and the corresponding consequences must be effectively characterized for reliable damage estimation. Some drift-based fragility functions have been proposed based on experimental datasets in literature; however, the high dispersion and inconsistencies of findings hinder their reliability in damage assessment. Therefore, this paper aims to derive a reliable fragility curve for reinforced concrete infilled frames using numerical analysis. The analysis models were designed based on different infill parameters, including type of panel, infill strength, wall thickness, and aspect ratio. The cracking and crushing of concrete and masonry were simulated using the total strain crack model. The findings were validated against several experimental studies in the literature. A new damage state definition based on visible cracks ratio was proposed. The results indicate that damage capacity, crack pattern, and failure mode are strongly related to wall properties. It was also observed that infill strength and the presence of opening have a significant influence on the fragility of masonry infill.