Abstract: A three-dimensional dam-reservoir-foundation dynamic interaction model is developed to evaluate the seismic performance of high arch dams, based on the endurance time analysis method (ETA). It takes inputs of 10 seismic acceleration time history curves synthesized using the target response spectra, and adopts structural performance indexes: the damage volume ratio of dam body, the relative streamwise displacements at the dam crest and heel, and the joint opening of crown cantilever. We formulate a relationship between the limit state and structural performance index by defining different performance levels of the dam-foundation system, so that we can draw its vulnerability curves. The results show that with an increasing input time of the seismic time history, the dam responses intensify, and the sensitivity of different response indexes to seismic intensity is different. And the responses calculated using the ETA method and the incremental dynamic analysis method (IDA) are nearly the same. When different evaluation indexes are used at the same performance level, the corresponding probabilities of exceedance will be different. Therefore, different structural response indexes should be considered comprehensively in evaluation of the seismic structure performance, and the index with the largest probability of exceedance at different performance levels should be selected for analysis.

Key words: high arch dams, seismic response analysis, endurance time analysis, vulnerability analysis, ground motion characteristics