Effect of corrosion on self-centering energy dissipative devices

This study reveals the effect of corrosion on the performance of typical self-centering energy dissipation devices for seismic resilience enhancement. Two types of SC devices, namely, high-strength steel ring spring-based SC damper (HSSR damper) and SMA ring spring-based SC damper (SMAR damper), are examined. These specimens were subjected to 720 h' accelerated corrosion, corresponding to roughly 20 years' exposure to city out-door environment. Numerical studies are carried out in ABAQUS to further interpret the test results. Among other important findings, the tests showed that the HSSR damper is likely to lose its self-centering capability after corrosion. The high-strength steel (HSS) rings were severely corroded, and the restoring force provided by the rings was insufficient to overcome the friction action. The SMAR damper showed much reduced sensitivity to corrosion. For both dampers, there was no damage to either the SMA/HSS rings or the other components under repeated loading, implying a low risk of corrosion-related low-cycle fatigue failure. The numerical study implies that the friction condition over the entire contact surface is not identical once the damper experiences corrosion. A "two-region modelling strategy" with a smaller friction coefficient and a larger friction coefficient leads to satisfactory agreements with the test results for the corroded HSSR damper. For the SMAR damper, a constant friction coefficient for the surfaces between inner and outer rings has been found to be appropriate for both noncorroded and corroded cases. Based on the limited experimental and numerical data, it is recommended that anticorrosion measurement should be mandatory for HSSR dampers. Overstrength due to the long-term effect should also be considered in the design of HSSR dampers from a life-cycle design point of view. If no special anticorrosion measurement is applied, an overstrength factor of 1.3 may be considered. Overstrength may be ignored for SMAR dampers. By representing the key components of SC devices as a group of springs, the analytical description of considered SC devices can be obtained.