Comparison of seismic fragility analysis methods for arch dams

This study focuses on the seismic fragility analysis of arch dams. The multiple stripe analysis(MSA), cloud analysis(CLA), and incremental dynamic analysis(IDA) methods are compared. A comprehensive dam-reservoir-foundation rock system, which considers the opening of contraction joints, the nonlinearity of dam concrete and foundation rock, the radiation damping effect of semi-unbounded foundation, and the compressibility of reservoir water, is used as a numerical example. 225, 80, and 15 earthquake records are selected for MSA, CLA, and IDA, respectively. The results show that MSA provides satisfactory fragility analysis, while both CLA and IDA have assumptions that may lead to deviations. Therefore, MSA is the most reliable method among the three methods and is recommended for the fragility analysis of arch dams. It is also shown that the choice of demand level affects the reliability of fragility curves and the effect of the material uncertainty on the fragility of the dam is not significant.