Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 58 2 2026 04 21 Comparison of Conventional and Energy-Based Methods in Fragility Assessment of Steel Moment-Resisting Frames Comparison of Conventional and Energy-Based Methods in Fragility Assessment of Steel Moment-Resisting Frames 243 266 6074 10.22060/ceej.2026.25017.8374 FA Hossein Dehrouyeh PHD candidate, Department of Civil Engineering, Qa. c., Islamic Azad University, Qazvin, Iran. Ali Delnavaz Assistants professor, Department of Civil Engineering, Qa. c., Islamic Azad University, Qazvin, Iran. Reza Farokhzad Assistants professor, Department of Civil Engineering, Qa. c., Islamic Azad University, Qazvin, Iran. Mehran Seyed Razaghi Assistants professor, Department of Civil Engineering, Qa. c., Islamic Azad University, Qazvin, Iran. Journal Article 2025 10 31 <strong><span>Methods for generating fragility curves in buildings are generally based on the maximum inter-story drift. Moradi and Abdolmohammadi (2020) proposed an energy-based method. They stated that by considering the plastic strain energy in high-rise structures as an engineering demand parameter, fragility can also be derived. The aim of this study is to compare the maximum inter-story drift-based method and the energy-based method in 4-, 8-, and 12-story steel buildings. For this purpose, after initial design, the structures were modeled nonlinearly in PERFORM-3D software and subjected to 20 near-fault ground motion records. Incremental Dynamic Analysis (IDA) curves were extracted using both the energy and maximum drift methods and compared with each other. Finally, by calculating the energy limit states at two performance levels—Life Safety (LS) and Collapse Prevention (CP)—the fragility curves at these two levels, along with the elastic level, were computed and compared with the maximum drift-based method. The results showed that in low- and mid-rise structures, the maximum drift-based method provides a more conservative fragility estimation compared to the energy-based method. For example, the probability of exceeding 50% of the LS level in the energy-based method for 4-, 8-, and 12-story buildings occurs at peak accelerations of 1g, 1.25g, and 1.45g, respectively, while in the conventional method this occurs at peak accelerations of 0.65g, 0.9g, and 1g, respectively.</span></strong> <strong><span>Methods for generating fragility curves in buildings are generally based on the maximum inter-story drift. Moradi and Abdolmohammadi (2020) proposed an energy-based method. They stated that by considering the plastic strain energy in high-rise structures as an engineering demand parameter, fragility can also be derived. The aim of this study is to compare the maximum inter-story drift-based method and the energy-based method in 4-, 8-, and 12-story steel buildings. For this purpose, after initial design, the structures were modeled nonlinearly in PERFORM-3D software and subjected to 20 near-fault ground motion records. Incremental Dynamic Analysis (IDA) curves were extracted using both the energy and maximum drift methods and compared with each other. Finally, by calculating the energy limit states at two performance levels—Life Safety (LS) and Collapse Prevention (CP)—the fragility curves at these two levels, along with the elastic level, were computed and compared with the maximum drift-based method. The results showed that in low- and mid-rise structures, the maximum drift-based method provides a more conservative fragility estimation compared to the energy-based method. For example, the probability of exceeding 50% of the LS level in the energy-based method for 4-, 8-, and 12-story buildings occurs at peak accelerations of 1g, 1.25g, and 1.45g, respectively, while in the conventional method this occurs at peak accelerations of 0.65g, 0.9g, and 1g, respectively.</span></strong> https://ceej.aut.ac.ir/article_6074_2281f5c898351dbc6dace2ba201e7948.pdf