2024 Volume 80 Issue 13 Article ID: 23-13153
The observation of two magnitude 7 earthquakes at the same location, such as the 2016 Kumamoto earthquake, is unprecedented in the history of Japanese seismic observations and has made us aware of the possibility that seismically designed structures may experience multiple large seismic motions. In view of the possibility that bridges may also be subjected to multiple large seismic loads, the authors have investigated the hysteresis characteristics of single-column RC piers after being subjected to a loading history equivalent to one earthquake load using cyclic loading experiments. The results of previous experiments have shown that the ratio of the reduction in equivalent stiffness of the second loading to the first loading history has a linear relationship with the range of the first loading, but in this paper, the results of new loading experiments show that the ratio of the reduction of the equivalent stiffness has a linear relationship with the range of the first loading only up to the limit state 2. The paper details that the results of the new loading tests show that the rate of reduction of the equivalent stiffness has a linear relationship with the range of the first loading only up to the limit state 2.
