Sub structure on-line tests on braced frames with self-returning joint mechanism

A Ni-Ti-Co alloy exhibits shape memory effect, pseudo-elasticity, and these transition properties depending on the temperature when used. This paper examined a first-step application of such an alloy to an earthquake resistant structural system by making and testing a pseudo-elastic bracing system. Substructure pseudo-dynamic tests were performed to examine the behavior of pseudo-elastic bracing system during an earthquake when combined with fictitious hysteretic dampers. A pseudo-elastic bracing system is better to be used with other hysteretic elements such as a hysteretic damper. A damper provides energy dissipation within small displacement levels, and a pseudo-elastic bracing system works in turn as a back-up/fail-safe system when an accidental failure of damper or damper interface occurs, and also it helps to pull back the structure to the original position by uninstalling the damper after earthquake.