Investigation of Sediment in the reservoir on Seismic Damage of Concrete Gravity Dam in the Near-Fault and Far-Fault Ground Motions

Abstract

Sediment in the dam’s reservoir has a significant role on mitigation of dynamic response of concrete gravity dams and also the seismic response of dams in near-field motion can be considerably different from those observed in the far field and the near-fault ground motions can cause considerable damage during an earthquake. This paper presents results of a study aimed at evaluating the sediment effects in the near-fault and far-fault ground motions on nonlinear dynamic response and seismic damage of concrete gravity dams including dam-reservoir-foundation interaction. For this purpose, 3 as-recorded earthquake records which display ground motions with an apparent velocity pulse are selected to represent the near-fault ground motion characteristics. The Shafaroud gravity dam, which is selected as a numerical application, is subjected to a set of as-recorded near-fault and far-fault strong ground motion records and three different level of sediment are assumed. Results show that in the near-fault horizontal earthquake with assuming 2 m sediment height a 3.67% reduction and with 8 m sediment height a 10.33% reduction in dam crest displacement are obtained but in far-fault ground motion reservoir sediment do not have a sable pattern effect on dam’s response. Therefore, any dam must be evaluated for sediment effects on its dynamic response individually.

Keywords

• gravity dam
• sediment
• nonlinear dynamic analysis
• concrete damage plasticity
• near fault motion
• far fault motion
• seismic damage