Fragility functions of existing buildings play a fundamental role in seismic risk mitigation policies. The latest methodology developed by the authors and their co-workers for estimating direct losses from earthquakes in reinforced concrete (R/C) buildings are presented; they concern the derivation of capacity curves and vulnerability (fragility) curves in terms of peak ground acceleration (PGA), as well as spectral displacement, for all types of R/C buildings that are common in Albania. The vulnerability assessment methodology is based on the hybrid approach, which combines statistical data with appropriately processed results from nonlinear dynamic or static analyses that permit interpolation and (under certain conditions) extrapolation of statistical data to PGAs and/or spectral displacements for which no data is available. A detailed discussion of the limitations of the hybrid approach is provided, along with a proposal for improving the quality of results by applying a weighting technique to both the analytical and the statistical input data. In this paper, a procedure to develop analytical fragility curves for Moment Resisting Frame Reinforced Concrete building is presented. The design of the selected building typologies was performed according to the codes at the time of construction using force-based methods and the state of the practice at the time of construction.
