ABSTRACT
Under seismic actions, the induced damage in critical regions of a CFT column could be attributed to cumulative damage caused by repeated loading with different displacement levels after yielding. To develop a more rational damage criterion for circular CFT columns subjected to a series of earthquake excitations, an experimental study is undertaken to investigate the cumulative damage and relationship between low cycle fatigue life and displacement amplitude. The results of the testing containing both standard cyclic loads and constant amplitude tests are summarized in this paper. The low-cycle fatigue characteristics of typical flexural CFT columns are discussed. For comparison, a confined CFT column (CCFT) confined with steel collar was also tested, which showed improved fatigue life. A fatigue life expression is developed that would be used in damage-based seismic design of circular CFT columns.
