Development of Fragility Curves for Brick Infill Walls in Steel Frame Structures

Brick infill walls are one of the most common types of nonstructural elements used for exterior enclosures as well as interior partitions in steel frame buildings. The recent earthquakes have shown that damage to masonry infill walls may cause danger for human lives and dramatically affects economic losses. The damage estimation of masonry infill walls and the effects within the corresponding consequences of the performance-based earthquake engineering need fragility functions. The procedure implemented in this study is based on incremental dynamic analyses of two models, i.e. with and without brick infill walls. The primary objective is to develop fragility curves that permit the estimation of damage in masonry infill walls. Comparative analyses were conducted among the models considering four damage levels. The increase in the height has reduced the probability of damage to infill walls, so there was slight damage in drifts less than 3%. Therefore, with increases in stiffness, the probability of damages to the infill walls will increase. The fragility curves obtained by HAZUS show that there is a negligible variation in the infill walls seismic fragility estimated by the number of bays.