Robustness of Performance-Based Plastic Design Method for SMABFs

Shape memory alloys (SMAs) are gaining increasing attentions from earthquake engineering community, due to the superleastic property, which is capable of offering energy dissipation capacity and recentering ability to various structural systems. SMA braced frames (SMABFs) are emerging as promising frames with advanced seismic resilience. Recently, the performance-based plastic design (PBPD) method was developed for such structural system. However, the robustness of this design approach still needs rigorous examinations by addressing the effects of defining different performance targets or using different seismic design spectra in the design procedure. In doing so, examinations were carried out from two perspectives. The first one set various performance targets combining different interstory drift ratio and brace ductility demand in the design procedure based on the design basis earthquake spectrum, and then the resulting SMABFs were subjected to earthquake ground motions corresponding to design basis hazard level. The second one conducted the design procedure at three seismic hazard levels representative of frequently occurred earthquake, design basis earthquake, and maximum considered earthquake, respectively, and then assessed the seismic performance upon earthquakes associated with three seismic intensities. The analytical results show that the designed frames as per the PBPD method always coincide with the performance targets very well, regardless of the prescribed targets and adopted design spectrum. Therefore, this paper provided sound results which successfully demonstrated the high robustness of the previously developed PBPD method for SMABFs.