Seismic performance evaluation of a century‐old RC columns for railway's structural concrete

Since the Great Kanto Earthquake of 1923 in Japan, reinforced concrete (RC) has been adopted for railway bridge piers, and some of these structures, now over 100 years old, continue to support transportation in the capital city of Tokyo. Evaluating the seismic performance of these few remaining RC structures has become an urgent issue. Because these structures predate the industrialization of deformed bars, all reinforcing bars used were plain round bars, and the anchorage details differ significantly from current design specifications, which are based on deformed bars. Therefore, current seismic performance evaluation methods cannot be directly applied to them. This study experimentally verifies the seismic performance of century-old RC columns through a series of component experiments and, as a part of this effort, develops a nonlinear response analysis method for RC columns using round bars with inferior bond characteristics. As a result, it was shown that many RC bridge piers designed and constructed 100 years ago still provide sufficient deformation capacity, owing to large rotational capacities induced by pull-out of longitudinal reinforcement from the footing. This also reduces damage to structural concrete in the column body, indicating that a number of these structures still may satisfy current seismic performance requirements, an assessment scheme of which is proposed practically as well.