Seismic performance of concrete gravity dam under varying water level and dam height

Concrete gravity dam is a massive structure that uses its weight to resist the forces. However, strong ground motions can lead to the structure's failure. Using the material properties of the Koyna dam, a 2D nonlinear numerical analysis model is developed in ABAQUS Software using the Concrete Damage Plasticity (CDP). The Incremental Dynamic Analysis (IDA) was performed to obtain the IDA curve for the concrete gravity dam, considering variations in dam height and water level in response to single and repeated earthquake events. Seven ground motions were scale as per the Eurocode 8. IDA curves were generated to illustrate the damage states at various ground motion intensities. The result at 50 m dam the ultimate displacement range from 28.04 mm at (full, single) to 39.31 mm (half, repeated). As for the 100m dam the maximum displacement increased from 48.45mm (full, single) to 54.59 mm (half, repeated). It shows that the higher dam receives significantly greater damage due to greater mass. Subsequently, dams with lower water level reduced the hydrostatic resistance caused to higher displacement. Furthermore, the dam received greater destruction due to repeated earthquakes than a single earthquake event. This finding emphasize the needs of incorporating the water levels, dam height and repeated seismic load in dam safety design and retrofitting strategy.