Abstract: Previous studies have shown pulse-type ground motions have a significant impact on structure seismic safety, but few focused on the overall dynamic damage characteristics of concrete gravity dams under such motions. Based on the Koyna gravity dam project, this study develops a multi-coupling simulation model that can describe satisfactorily the dynamic damage evolution process of its dam concrete and dam foundation rock mass. We select ground motion records of pulse and non-pulse types from the strong earthquake database NGA-West2, and simulate and analyze its response spectrum characteristics. From the simulations, the damage areas, energy consumption, displacement responses, and other overall damage evolution characteristics of the dam body are examined in detail. The results show that pulse ground motions pose a significant impact on the overall damage to the dam body and its foundation, and can cause greater energy dissipation and stronger displacement responses of the structure system. After the ground motions, the residual deformation of the dam subjected to pulse-type ground motions is obviously larger in the dam’s head part than that of the non-pulse type, but it shows little effect in the lower part.

Key words: concrete gravity dam, damage evolution, pulse type, non-pulse type, ground motion