Development of Fragility Curves for Reinforced Concrete Buildings

Algeria has experienced numerous destructive earthquakes, resulting in significant loss of human lives, buildings, and equipment. To mitigate this risk, this study aims to quantify the potential damage to existing strategic buildings in the city of Constantine, located in the northeast of Algeria. Many of these buildings are old, designed and constructed during the colonial era before the implementation of the Algerian seismic code. Thus, they are required to be strengthened and retrofitted. Methods: The LM2 method, defined in RISK-UE (WP4), based on nonlinear static analysis and spectral response, is used to develop fragility curves. In this context, a structural system mainly consists of momentresisting reinforced concrete frames with partial infill walls. In this study, three types of strategic buildings are considered: low-rise (two stories), mid-rise (four stories), and high-rise (six stories). The current Algerian seismic code RPA99/ version 2003 (MHUV 2003) is used to assess the seismic demand. As a result, capacity curves are developed for two primary directions: local and global behavior, identified according to the limits specified in FEMA 356/273 and ATC 40. Based on these results, fragility curves are generated, defining four damage states: slight, moderate, extensive, and complete in terms of spectral displacement.