Discussion on Rayleigh Damping Matrix Modeling of High-rise Arch Dam Seismic Response Analysis in Time Domain

The effect of Rayleigh damping matrix modeling on the computational accuracy of the seismic response of high-rise arch dams in the time domain is discussed in this study. The dynamic characteristics of a 240 m-high arch dam were analyzed under bidirectional and three-directional seismic excitations with different Rayleigh damping matrix modes. Eight Rayleigh damping matrix models associated with two specific reference frequencies have been established, where the first reference frequency is taken as the first or second frequency of the system, while the second reference frequency is set to be the fifth or sixth frequency of the system, as well as the peak frequency and the center of gravity frequency of the seismic response spectrum. The results show that the selection of damping coefficients has a significant influence on the calculation accuracy of structural dynamic responses for high-rise arch dams, which are long-period systems. It is suggested that the river-direction fundamental frequency of the arch d