Abstract: Uncertainty in ground motions is a significant factor in the seismic safety evaluation of arch dams. The physical-based direct numerical modeling can consider different earthquake scenarios and generate site-specific earthquake motions, manifesting great application prospects in earthquake engineering. This study examines the scattering of nonlinear seismic responses of an arch dam to ground motions that are simulated numerically for three earthquake scenarios, focusing on the dynamic responses－including concrete damage, contraction joint opening, and displacement. Results show that the responses feature significant variability under different earthquake scenarios even if the rupture fault, magnitude, and stream peak ground acceleration at the dam site all remain consistent. The findings shed light on the scattering of dam responses and promote application of the ground motions generated by direct numerical simulations.

Key words: arch dam, seismic response, ground motion simulation