A NEW REPAIRABLE CONCENTRIC BRACE WITH DUAL-PERFORMANCE

Due to considerable damages of the infrastructures caused by earthquakes and following high-cost reconstructions, the design and utilization of the repairable structures have been intensified recently. In designing the repairable structures, a serious concern is that most of the structural systems use only singleperformance fuse elements, and they, inevitably, are designed for the largest possible earthquakes. Consequently, for moderate earthquakes, the considerable damages of other structural members are very likely (Hosseini Hashemi & Alirezaei, 2015; Hosseini Hashemi & Moaddab, 2017; Zahrai & Vosooq, 2013). From another point of view, when an earthquake happens, seismic demand at the beginning moments is not high. Therefore, the activation of the highest available stiffness is not required and is not recommended. The main reason is that higher stiffness results in higher subsequent demand. Not addressing this issue is one of the major drawbacks of the single-performance systems. In this regard, in current paper, a dual-performance repairable concentric brace is introduced (Figure 1). In this brace, upon the beginning of earthquake the first series of yielding plates (that are parts intended to absorb energy and are intentionally designed to be damaged by the earthquake force to protect main parts and to avoid their damage) react against the imposed forces and start to absorb energy, while the second series of plates are still inactive. If the displacement (drift) caused by the earthquake becomes greater than a certain amount, the second series of yielding plates will be activated too. In other words, the activated stiffness of the structure increases when the demand increases. Therefore, using the proposed system, for all levels of seismicity, a very well energy absorption is provided and intended structural elements will be protected. The yielding plates are easily replaceable and the structures can be repaired immediately.

Keywords:

Repairable , Dual-performance , Concentric brace , Yielding plates , Finite element method