Influence of Quasi-Static Loading Patterns on Fragility Curves of Reinforced Concrete Columns

This paper examines the effect of various cyclic quasi-static loading patterns on the fragility curves of reinforced concrete (RC) columns, which are crucial structural elements prone to failure under seismic loads. Fragility curves describe the probability that an engineering demand parameter (e.g., drift ratio) will exceed a specific damage state. A comprehensive database, consisting of experimental tests from ۲۳۱ RC columns subjected to different quasi-static loadings, was compiled and analyzed. The study investigates how variations in loading patterns influence fragility indices of the columns, such as drift ratio. Results show that columns subjected to more intensive loading protocols (Cluster ۳) exhibited higher drift responses, with median drift values reaching approximately ۳.۷۴% at ۱۰% degradation, compared to ۱.۹۹% for Cluster ۱, which represents lower-amplitude loading. Additionally, fragility curves derived for key damage states, such as yield and ۱۰% degradation, indicate a significant increase in seismic vulnerability with higher loading intensities. These findings provide valuable insights for improving seismic design methods and enhancing earthquake-resistant reinforcement standards.

کلیدواژه ها:

quasi-static loading ، fragility curves ، RC columns ، drift ratio ، data-driven clustering ، damage state ، dynamic time warping (DTW)