| Raising the height of existing dams can be one of the most effective solutions to meeting the changing needs of flood control and water use in river basins. Meanwhile, evaluating the structural safety of dams against large scale earthquakes is one of the most important issues in the construction of new dams and the sustenance of existing dams. In this paper, the seismic behavior of raised concrete gravity dams during large scale earthquakes is investigated through the use of numerical simulations, including a linear analysis and a non-linear dynamic analysis that considers the crack propagation accompanied by tension softening of dam concrete. The analyses revealed that the damage caused to a raised concrete gravity dam resulting from a large earthquake is not the same as that of a newly constructed dam with the same shape. Further, it was determined that the damage depends on the height of dam raising and the water level of the reservoir during the raising work. Based on these results, it was pointed out that when evaluating the effect of seismic motion on a raised concrete gravity dam through the use of dynamic analysis, the process of raising work, including the placement of new concrete, and the actual water level of the reservoir during the raising work should be properly taken into consideration. |
