Fuzzy analytical hierarchy process and component importance measures for selection optimal intensity measures and development fragility curves in bridges

The process of selecting optimal intensity measures (IM) in complex systems is a multi-criteria decision-making (MCDM) approach. However, previous studies mainly assumed constant weights for performance metrics and neglected the importance of various components. To overcome these challenges, a framework that was formulated based on the order preference by similarity to the ideal solution (TOPSIS), using the fuzzy analytical hierarchy process (FAHP) and component intensity measures (CIMs) is proposed. 3200 multi-span continuous concrete I-girder (MSCC-IG) and multi-span simply supported concrete I-girder (MSSSC-IG) bridges are randomly paired with a suit of input motion through probabilistic seismic demand analysis (PSDA). FAHP reveals that among different performance metrics proficiency and practicality have the highest and the lowest weight in the selection of optimal IM, respectively. The findings of the proposed framework show that the foundation, which has the lowest CIMs, has an insignificant impact on the selection of optimal IM in bridges. Moreover, the Sa(1,2), which is a summation of 0.80 and 0.20 spectral acceleration in the first and second modes of vibration in bridges, respectively, is the ideal IM in the majority of components of bridges. Fragility outcomes of this study reveal that the vulnerability of MSSSC-IG bridges is higher compared to MSCC-IG bridges at the system level.