Rigorous versus less-demanding fragility relations for RC high-rise buildings

Analytical seismic scenario-based probabilistic fragility relations form the spine of earthquake risk assessment and mitigation of RC high-rise wall buildings. In this study, a framework is proposed to develop both rigorous (refined) and less-demanding (cheaper) fragility relations (CFC) for such structures. Multi-record incremental dynamic analysis (MRIDA) is employed using a new scalar intensity measure and net inter-storey drift as a consistent global damage measure for varying heights of buildings. To illustrate the framework, a 30-storey wall building located in a multiple-scenario earthquake-prone region is analysed. The refined fragility sets are derived using 40 real earthquake records representing two seismic scenarios, while the proposed methodology to develop less-demanding SSB fragility relations employs a considerably lower number of earthquake records. In this methodology, a new record selection criterion and a fragility curve tolerance factor are introduced. Finally, the two fragility relation sets for the reference structure are developed, assessed, and compared to provide insights into their features and accuracy. Using the proposed methodology, the study revealed that fairly reliable seismic scenario-based fragility sets can be developed for RC high-rise buildings with a significant reduction in computational time and efforts. The proposed framework is generic and can be implemented to deriving refined and less-demanding fragility relations for RC high-rise buildings of different configurations and structural systems.