Seismic performance and fragility functions of confined masonry old infrastructure with handmade bricks

In several countries, confined masonry structures with handmade bricks were built for common to essential infrastructure. These bricks were made by clay using artisanal ovens; therefore, they have mechanical properties less than seismic codes currently recommend. Many of these buildings are one to three stories and were designed following past design codes or were built without considering any design codes. There is an uncertainty of the strength or ductility for these buildings to resist a severe earthquake event. For this purpose, this study aimed to develop fragility functions as way to estimate and quantify the vulnerability of these structures. This research describes a methodology to find fragility functions based on a nonlinear model with three levels of masonry handmade bricks. Experimental test data was used to validate the proposed model during the calibration process. Incremental dynamic analyses were developed for 11 pairs of seismic records for both orthogonal directions. Fragility functions reported a high probability of collapse for demand levels from a design earthquake to maximum capable earthquake.