In the present paper, a new numerical approach here named as Developed Energy Dissipation Algorithm (DEDA), which is based upon finite element analysis is utilized for evaluating the material damping ratio and Rayleigh damping coefficients in the dynamic time history analysis of an existing concrete gravity dam. In this approach, damping ratio takes a function of unit dissipation energy, which is also a function of stress amplitude. An iterative process is used to update the damping ratio in every time step of analysis. For the numerical example, the Pine Flat concrete gravity dam under Taft ground motion is selected. The dam crest displacement of the DEDA approach is compared with the so-called computer program EAGD-84 and the results show good agreements. Comparing the results of the DEDA approach with the Traditional Rayleigh Damping Method (TRDM) gives the reasonable value, which agrees with the field tests.
