Experimental investigation of a low‐prestressed self‐centering energy dissipative brace

Self‐centering energy dissipative (SCED) braces have the potential to contribute greatly to building resiliency, because the braces can limit both maximum and residual story drifts during earthquakes. An obstacle to widespread adoption of existing SCED systems is that they require high prestressing forces, corresponding to more than half of the brace yield strength. To address this problem, a new low‐prestressed SCED (LP‐SCED) system has been proposed, which has a flag‐shaped force–deformation hysteresis but needs only a low level of prestressing force. This paper presents the results of an experimental investigation to establish the properties of the new system's key components, as well as prototypes of the full brace specimen. The tested system had a prestressing force equal to only 3∼4% of the brace yield force. The tested systems had a stable, flag‐shaped force–deformation hysteresis relationship, even after being subjected to deformations corresponding to 3.4% story drift. Eventually, when the imposed deformations were sufficiently large, the brace stiffness increased dramatically, which helps to reduce drift concentrations that may be critical in braced‐frame structures under extreme earthquakes. The yielding and damage were restricted to the mild‐steel dissipaters, which could be replaced easily after each test, and in practice, they could be replaced easily after an earthquake.