Abstract

Arch dams are of great importance in the world. In Turkey, there are 1200 existing dams with different types. Arch dams are important due to their economic resource in irrigation and water supply which are significant to the homeland security and the agricultural economy. Researchers have been carrying out various studies on dams and their seismic resistance especially after the earthquakes that occurred in the recent years. Turkey is also located at one of the earthquake-active zones. In 1999, devastating earthquakes hit Turkey causing severe property losses and thousands of lives. Excessive ground deformation caused severe crack to the existing buildings. Therefore, it is important to investigate the seismic safety of the existing dams in Turkey. In this study, probabilistic seismic risk assessment has been carried out for arch dams: Gökçekaya, Oymapinar, Karakaya, Gezende, Sir, Berke, Deriner, Ermenek Dams. For these arch dams, structural resistances have been discussed. In addition, their resistances have been determined through time history analysis with 60 different ground motion data. After time history analyses, fragility analyses for arch dams have been carried out. The fragility analysis has been used to determine probability of exceedance. Via fragility analyses, level of risk and probability of exceedance have been determined. The exceedance probabilities of the yield and collapse limit states for arch dams in Turkey have been obtained for a realistic probabilistic determination. According to the results, the role of probabilistic seismic risk assessment in dam safety decisions is addressed in detail.

Key words: Arch dams, probabilistic seismic assessment, structural assessment, time history analysis, fragility analysis.