Numerical Study of The Strength of Concrete Coating on The CFRD Dam

Earthquakes are one of the major phenomena affecting structures and engineers use design criteria to deal with their effects. In terms of the specific degree of safety for dams ‌, it is necessary that the design of large dams include the largest believable earthquake in hazard analysis and probability consideration regardless of the amount of time it returns in the design. Pebble dams have mainly concrete or asphalt coating, which in addition to impermeability to water, increases the stability of the dam. Since a number of gravel dams have been constructed in Iran and several other gravel dams are under construction, the study and analysis of this type of dam is very important for current and future studies of dam engineering. In this research, pebble dam modeling will be done in Abacus software as well as model validation. First, the model presented in the reference article is modeled and validated. The model used in validation and this research is Musouchura Dam. After ensuring the accuracy of modeling and analysis, the effect of concrete strength of dam cover under the effect of selected accelerometers and by changing the strength of concrete and also the effect of considering the damping of concrete were measured and finally the results were compared. The accelerometers used in this study are Northridge, Bam, San Fernando and Tabas. Changes in concrete strength in three types C20, C25 and C30 with nominal strength of cylindrical compression specimens of 20, 25 and 30 MPa were made and this increase in strength is about 8 to 10% in reducing lateral displacement under selected accelerometers in the dam crown has it. Considering the damping effect in concrete with a value of 0.0325, under selected accelerometers, there is a change of about 3% in the lateral displacement of the dam crown, while it has little effect on the tensile degradation of the concrete surface.