Seismic performance of unbonded columns and isolator built-in columns based on cyclic loading tests

ABSTRACT: The bond between longitudinal bars and the concrete results in concentration of damage at a specific localized region. One of the measures to mitigate such a concentration of damage at the plastic hinge is to unbond the longitudinal bars from the concrete. By appropriately unbonding the longitudinal bars at an interval with length Lub as shown in Figure 1, the deterioration of longitudinal bars is mitigated resulted from reduced strain at the interval Lub.