Near-fault seismic damage patterns and failure scenarios prediction of concrete gravity dams using nonlinear incremental dynamic analysis

Performance based earthquake engineering approach has been under evolution for seismic safety assessment of structures. Qualitative and quantitative definition of seismic performance levels is major challenge of concrete gravity dams. The main purpose of this article is damage patterns and failure scenarios prediction of structure while they prepare a suitable basement to determine dam seismic limit-states. Therefore nonlinear incremental dynamic analysis has been applied to dam-reservoir-rigid foundation system of Pine Flat gravity dam as a case study under the pulselike near-fault records. Then the critical zones of dam body have been recognized using a new way and a series of potential crack paths has been found. The mentioned above paths have been validated through comparing with authoritative published reports. We observed that the structure is damaged in certain patterns under near-fault records. Also formation of full crack in dam body is possible only in four paths before the possibility of total collapse. Hence three failure scenarios of concrete gravity dam have been defined in this research, in addition to damage patterns prediction. The results show that the safety level of concrete dam is increased substantially when the crest displacement response or drift ratio is limited to the conservative value.